The Windows Phone 7 rumour mill has been hastily gathering momentum for some months, and now it's finally a reality. The WP7 handsets may be great pieces of hardware, but we all know that the success or failure of the new OS is going to come down to one thing - the apps.

If the new phones are to compete with the big boys, such as Android, then they're going to need to really impress us all when it comes to content. And not just daft apps that'll never see the light of day after launch week. We already know that Microsoft has tied up a deal with EA to feature a clutch of games from Windows LIVE Arcade, but what about the likes of Google, Skype and Spotify - stuff that you'll actually want to use on a daily basis and will affect your decision on whether to opt for Microsoft's new kid on the OS block.

We've drawn up a list of all of the major apps that we want to see on Windows Phone 7, and then hunted down the developers to see whether they're available or coming soon.

There are already a few third-party WP7 apps around for Twitter, such as Twozaic, but the social micro-blogging site has also prepared its own app for the new OS launch. Designed specifically to suit the WP7 handsets' Metro UI, the app will support multiple accounts and will also let you browse Twitter content without having to sign in or without even having to sign up for Twitter in the first place. No doubt it will be just a matter of time until users decide which of the Twitter apps become the standard.

The wildly popular music service very recently launched on the Windows phone 6 platform, with the makers confirming that it will also be available soon on WP7. Already available on iPhone, Android and Symbian, the app enables music fans to listen to millions of tracks by streaming them over Wi-Fi. You can also download playlists so that they can be played in locations where you've got no connection, such as on a plane. However, if you want to use Spotify on your phone, then you'll need to stump up the cash for a premium account. With Windows Phone 7 having its own Zune music streaming platform integrated, it'll be interesting to see how many users opt for Spotify instead.

Facebook has to be one of the most important apps around, with so many of us now using the site from our mobile phones. So far, the social networking site hasn't gotten back to us about a separate app, but along with Xbox LIVE, Facebook integration will be standard on the new Windows Phone 7 handsets, so you should be able to keep your friends up to date with your activities, 24 hours a day.

Unfortunately for Mozilla fans, it doesn't look like Windows Phone 7 will be getting a Firefox Mobile app any time soon. In fact, the company has put all its Windows Mobile development on hold for the foreseeable future as a result of Microsoft closing off development to native apps. Although Mozilla has hinted that it would definitely be interested in building a Firefox app for WP7 in the future, if Microsoft were to provide it with a way of doing so.

Although Foursquare has been holding its ground since the introduction of other location-based social apps, such as Facebook Places and location tweets on Twitter, it has yet to make any official announcements about a WP7 app. However, it sounds like there's one on the way as Foursquare told Pocket-lint: "We think Windows Phone 7 is great and we're working with Microsoft. We should have something to announce on this shortly".

With the popular VoIP service recently launching on Android, we thought that it might have prepped one ready for the Windows Phone 7 launch as well. Not so, it seems. Skype told Pocket-lint: “we are not at liberty to share any future looking products at this time". We're going out on a limb here and speculating that this means that there might well be an app coming at some point in the future. Because if there was no future product, then they'd be able to talk about it, right?

The world's largest online marketplace has joined the Windows Phone 7 party with a new app that's available on launch day. Just like its apps available on other plaforms, eBay's WP7 service enables you to search, bid and buy and check your selling activity when you're on the fly. According to the brand, the new app has been carefully designed to work with Microsoft's panoramic user interface, with eBay’s vice president of mobile and platform business solutions, Steve Yankovich, commenting: “We built this app from the ground up to take full advantage of Microsoft’s operating system. Users can slide through all their eBay activity and receive real-time notifications on best offer and bidding activity, and items ending soonest”. The free download will be available to users in the UK, USA, Australia, Canada, France, Italy, Spain and Germany.

If you've used this app before on other platforms, then you'll know how it helpfully condenses Facebook, Twitter and all the other social networking sites that you belong to into one handy place. Designed to work seamlessly with the Windows 7 and Mac versions of the software, the app will let you do all of the usual things such as updating your status and commenting on photos. It also ups the ante thanks to its full integration with other services on the phone, such as Bing maps.

If you're a big fan of remote shopping, then chances are that Amazon will be top of your app wish list. Although we've yet to hear any official confirmation from Amazon, the Windows Phone 7 press conference included a demo of an Amazon app, so hopefully we should be hearing more about this one soon.

The first port of call for any self-respecting movie buff - the Internet Movie Database (IMDb) is a goldmine of film-related knowledge. Despite the annoyingly clunky re-design of the main site, it's still a fantastic point of reference to have at your fingertips when you're on the move, if only to settle any movie trivia-related arguments. Although nothing as been announced, an app was spotted by our eagle-eyed reporters during the Widows Phone 7 press conference demo.

It seems that the birds are very angry indeed. Microsoft used the icon as part of the online promotional materials for Windows Phone 7, apparently without consulting Rovio Mobile - the company behind the hit game. In fact, it was so upset, it tweeted it. Reading:

"We have NOT committed to doing a Windows Phone 7 version. Microsoft put the Angry Birds icon on their site without our permission".

While that might not be a no forever, it certainly hasn't done a lot for good relations. Don't expect to see Angry Birds on WP7 any time soon.

The familiar brand name is almost synonymous with GPS navigation technology, making it the go-to guy for all your mapping needs. However, you might be left feeling a little lost when you hear that TomTom told us that it has no plans for a WP7 app. However, you will get Bing Maps as part of Windows Phone 7, which will enable you to map destinations and then follow the written directions.

The popular online film rental site will have an app available from launch for the US market, which links into the Hub so that you can integrate your movie choices into the phone's user interface. As you'd expect, the app's functions include enabling you to order movies and letting you know when your choices are in the post. We're hoping that Lovefilm will announce something similar for the UK market, but there's been no official announcement just yet.

Hipstamatic is one of the stand out app hits on iOS. It's rare to see an app stand the test of time that isn't one of the already big established brands, so is it planning on doing the same on WP7. We asked, they answered:

"There is no talk at the moment for creating Hipstamatic for the Windows platform. We are a team of 5 with only 2 developers, so it's unlikely that we will port it over".

We'll call that a no.

Already available for iPhone, Symbian and Android, Touchnote is now also an option for Windows Phone 7 users, and is one of the few UK-based companies chosen as an official launch partner. The app enables you to take a photo and send it as a physical postcard from anywhere in the world. Within the UK, postcards are normally delivered the next day if ordered before midday. Prices start at $1.49, and will depend on the handset.

We also contacted several other brands to see if they have any apps coming to Windows Phone 7. These include, Lovefilm, Wikipedia, Sky+, Opera and Google. We haven't heard back from them yet, but we'll be sure to let you know if and when we do.

What do you think of the selection available? Which apps would you like to see on Windows Phone 7? Who else do you think is on the way and who won't touch it with a barge pole.