Rockstar has released a set of four videos showing off what you can do with the video editor including the PC version of GTA IV, and it's really quite impressive to say the least.
The PC game, released in Europe on 3rd December, allows you to hit F2 at any time to save the last 30-40 seconds of gameplay footage.
You can then open this recording in the video editor and alter things such as camera angle, filters and other visual effects. You'll be able to put things into slow motion, add text, change the music, and even edit together a number of clips to create a montage.
Of course, once you've finished, you can upload your masterpiece to a special page on the Rockstar Social Club website for everyone to see and admire. There's also the option to keep your videos in 720 and 1080p too if you prefer.
The example above is known simply as "Liberty" and certainly gives you something to aim for.