Best smartphones to look forward to in 2015

With the pace of smartphone evolution moving so fast, there's always something waiting in the wings. No sooner have you spied the latest handset, then there's anticipation of something else, the next big thing to envy.

We've rounded up the best smartphones for 2015, those we consider to be the best across all platforms, and we've regularly updated that list as the smartphone world has evolved.

You can find those in our Best smartphones 2015: The best phones available to buy today feature.

Here we're looking at those phones that haven't yet launched, those we know are coming, or are anticipated. As we run towards Mobile World Congress 2015, we enter the busiest time of the year for smartphone launches.

We'll be updating this list on a regular basis, with those device rumours we think are credible and exciting, and devices just announced but yet to hit the shelves.

HTC One M9 Hima

Of all the devices on this list, the HTC One M9 is the device that we think we know the most about. That's aided by HTC announcing its MWC 2015 press conference on 1 March, when you will see this device announced.

You can expect HTC to stick to a premium metal design, as well as offering those forward facing BoomSound speakers. The HTC One M9 is rumoured to launch with a Qualcomm Snapdragon 810 chipset and 3GB of RAM, suggesting plenty of power.

However it looks like HTC might stick to a 1920 x 1080 full HD display, and at 5 inches, rather than swelling it in size or resolution. That might have advantages when it comes to battery life.

Elsewhere there looks to be a radical change in cameras, with a 4-megapixel front UltraPixel sensor and 20-megapixel rear camera suggested, as well as HTC Sense 7 running on Android 5 Lollipop.

READ MORE HTC One M9 Hima rumours, release date and everything you need to know

Samsung Galaxy S6

Samsung didn't have the success it wanted with the SGS5, so we might see something of a revision of the format for the SGS6. Rumours of a metal-bodied phone are circulating, and with the A/Alpha handsets being something of a test bed for a new generation of devices. There's talk of  metal frame and tempered glass back for the SGS6.

We'd expect the SGS6 to offer a display around 5.2-inches, but it's still not known whether it will be Quad HD or stick to full HD resolution. We suspect Samsung will step up to 2560 x 1440 pixels to fend off Korean rivals LG.

It's been widely reported that Samsung isn't going to be using Qualcomm in its next run of smartphones. With the Exynos hardware performing well on previous devices, that might not be too much of a surprise: the SGS6 might all run on Samsung's in-house Exynos hardware.

We've also heard that Samsung is having a change of heart on its TouchWiz software, with reports that it's going to reduce the bloatware and come closer to Android, perhaps even pre-installing Microsoft apps.

We can also expect Samsung to continue to offer the heart rate sensor and fingerprint scanner. A 16-megapixel camera with optical image stabilisation is likely, with Samsung themselves saying that the SGS6 camera will be fantastic.

Samsung has lined up a press conference for 1 March, so we'd expect to see the Samsung Galaxy S6 launched there.

READ MORE Samsung Galaxy S6 release date, rumours and everything you need to know

Sony Xperia Z4/Z3S

Yes, the Xperia Z3 is fairly recent - and a very good phone - but it looks like Sony could already be preparing the next update to its flagship device. Arguably it doesn't need to, but the Xperia Z4 or Z3S will probably see an early-2015 launch.

Of all the devices forthcoming, least is known about Sony's plans and Sony isn't scheduling an event for MWC 2015.

There isn't a huge amount to go on, but it's suggested that we'll see a slightly new face on the Z4 with a repositioning of the front-facing speakers, and perhaps a step up to Quad HD resolution for the display. It's been suggested that the casing will be exactly the same, rather than there being a redesign.

Rumours suggest an updated camera too, but still with 20.7-megapixels and optical image stabilisation on the back. A boosted front camera is likely too, as is Android 5.0 Lollipop.

READ MORE Sony Xperia Z4 rumours

HTC One M9 Plus

There's plenty of speculation around HTC's plans for 2015, with rumour and counter-rumour. There's been a suggestion that HTC is using dummy devices to throw people off the trail of what's to come. But it looks like M9 launch might see more than one device.

The rumour of the HTC One M9 Plus has come up a couple of times, suggesting that there's going to be a bigger device launched alongside the regular M9. There's talk of a 5.5-inch display, so it's not much bigger than the 5-inches that we think the M9 will have.

But then images started appearing of a new device with Duo Camera alongside those rumours. We'd expect the internal hardware to be the same - Qualcomm Snapdragon 810, 3GB RAM - but using the Duo Camera would be an interesting move following its lukewarm reception in 2014.

It's also been suggested that the HTC One M9 Plus will be limited release, with the standard M9 being the global flagship.

READ MORE HTC One M9 Plus news and rumours

Samsung Galaxy S Edge

Samsung looks to be lining up not only the SGS6, but an Edge version of it too - the Samsung Galaxy S Edge (or should that be S6 Edge?).

Following the move it made with the Note family last September, the S6 Edge is rumoured to be a special edition, designed for limited release.

This time, however, it's going to have that curved edged display on both sides, so you'll be able to get the benefit whether you're using your left or right hand. It's thought that the system will work the same way it did on the Galaxy Note Edge, offering alerts, toolbars, scrolling feeds and so on.

Elsewhere we're predicting the Galaxy S Edge to have the same sort of specs as the SGS6, i.e., an Exynos chipset, 3GB RAM, Quad HD display. We're note sure if we'll see a metal body, but you can expect the S Edge to be more costly than the regular Galaxy S6, perhaps up to £800.

READ MORE Samsung Galaxy S Edge rumours

Sony Xperia Z4 Compact and Ultra

The Sony Xperia Z4 Compact is apparently going to arrive with 3GB of RAM, a 20.7-megapixel camera, 32GB storage, and a 4.7-inch screen with 1080p resolution. You can also expect a 3,000mAh battery, Cat 9 LTE, wireless charging and IP68 water and dust proofing.

The Sony Xperia Z4 Ultra should arrive with a 6.44-inch display with a QHD resolution. It should also come with 3GB of RAM but a smaller 16-megapixel camera and larger 4,000mAh battery. Unlike previous versions of the Ultra this model should also come with a stylus.

Will we see a full launch of the Xperia Z4 family at MWC 2015?

READ MORE Sony Xperia Z4 news

Huawei Ascend P8

Huawei has confirmed that the Ascend P8 is coming and that it will be launched at a global event in London on 15 April.

Aside from pinning a date on the launch of this new handset, Huawei has said little else about it and there's been no leaks to speak of either. However, given that the focus has been on thin and light, we'd expect that to continue.

Huawei has also used its own hardware, so it will probably come with the latest generation of HiSilicon chipset and with Huawei being one of the largest providers of telecommunication infrastructure, you can bet it will be well-specced for 4G LTE support too.

Huawei's big consumer play has often been the camera performance, so we'd expect something like a 13-megapixel rear and 8-megapixel front camera. 

Whether there will be an Arsenal FC special edition remains to be seen.

READ MORE Huawei Ascend P8 rumours and news

LG G4

The LG G4 could arrive with the smallest bezel on any screen yet, if the prototype devices shown off by LG are anything to go by.

We're expecting a screen around 5.7-inches that could be UHD or at least 2K. The processor will hopefully be a Snapdragon 810 64-bit chip with Cat 6 4G and 4GB of RAM.

Battery life and camera should also see improvements both in hardware and software.

The LG G4 isn't expected at MWC 2015, with LG having a slightly offset update cycle. There have been previous reports that the G3 will be given a year in the market before the update is announced, which would give us a date of late May or early June for the LG G4 release.

READ MORE LG G4 what to expect

Asus ZenFone 2

Asus has been one of the first companies to launch a new device in 2015. The Asus ZenFone 2 was launched at CES 2015.

Asus has stuck with Intel for the hardware, with an Intel Atom Z3580 paired with 4GB of RAM, which should make for a really powerful handset.

There's a 5.5-inch display, with 1920 x 1080 pixel resolution as well as a 13-megapixel camera on the rear. Asus is making great claims about this camera, saying it will offer low light performance like you haven't seen before. We'll be the judge of that.

The ZenFone 2 has rear volume controls, like the LG G3, and it ships with Android 5.0 Lollipop skinned with Asus' Zen UI.

Fortunately, despite some premium specs, the ZenFone 2 comes with the $199 starting price tag. We're yet to hear exactly where it will be on sale, however.

READ MORE Asus ZenFone 2 preview

Asus ZenFone Zoom

We didn't see this one coming, until Asus teased "optical zoom" in an oh-so-obvious way. But Asus now has a smartphone with optical zoom that was announced at CES 2015.

There aren't many cameras with optical zoom around and the ZenFone Zoom is a world away from the Samsung Galaxy K Zoom. Samsung's model is more like a camera, however, with 10x optical zoom and a 20MP sensor, along with Xenon flash. The Asus, however, is fairly slimline, cramming the 3x optical zoom 13MP camera into a body that's still pretty slim.

To assist that camera is laser autofocusing, but we're yet to see if this all fuses together nicely, or if it's a mish-mash experience.

Elsewhere the Asus ZenFone Zoom has a 5.5-inch display and will launch with Android 5.0 Lollipop, along with Zen UI. It's still some way off, however, with no word on when it might be available.

READ MORE Asus ZenFone Zoom eyes-on

LG G Flex 2

LG announced the LG G Flex 2 at CES 2015 in Las Vegas, bringing the second iteration of its curved phone.

Having listened to feedback from the original device, LG has made the new G Flex smaller, so it now has a 5.5-inch POLED display, which is more manageable than the previous. It has a full HD display now too, which at this size is nice and sharp.

But it's not just about the curve: the LG G Flex 2 has a Qualcomm Snapdragon 810 chipset with 2GB of RAM. It's 64-bit, supporting Android 5.0 Lollipop that it launches with and there's a 3000mAh battery to get you through the day.

The camera is a 13MP with laser autofocus, with LG saying that it's more capable than the LG G3. All in all, the LG G Flex 2 is an impressive package. If you had doubts about the original, this should quell them.

READ MORE LG G Flex 2 preview

Microsoft Lumia 1020 replacement/RM-1052

This rumour is a little on the loose side, but a newly-leaked image has appeared showing a Lumia model with a big camera bump on the rear. The Lumia 1020 was a mobile photography star, but has never been replaced and all of Microsoft's recent devices have been at the budget end of the spectrum.

There's a chance that you're looking at a new high-end PureView model, known as the RM-1052, but equally it could be a prototype of the cancelled Nokia McLaren.

But it's nice to dream that Microsoft Devices will fill the high-end with a 5-inch Windows Phone 8.1 device with a great PureView camera.

We're not convinced by the bodywork, the metal and plastic fusion doesn't look like a finished consumer device, but it could be the birth of a new photography star for 2015. An explosive launch at Mobile World Congress in 2015 perhaps? Let's dream about that.

READ MORE Microsoft Devices news and reviews

Google Project Ara

Created by Motorola, and now shifted over to Google after the sale of Motorola to Lenovo, Project Ara isn't due to early 2015 but is essentially an exoskeleton that allows users to modify what parts they want. That way someone that wants to spend the bulk of their budget on the camera, but doesn't need as much storage, can chose to upgrade that way. Perhaps one person will skip NFC in favour of faster 802.11ac Wi-Fi, for example.

There should also be third party components on offer that will allow for competitive pricing as well as new types of parts - like sensors. A person with diabetes may want a blood sugar sensor where another may not.

Users can also looks forward to different textured options that they can 3D print off at home themselves. The speed this phone can develop at, without costing us as much, is very exciting indeed.

READ MORE Google's Project Ara modular smartphone: Everything you need to know