Just wanted to spend a moment to mention the Prey Demo. Which is awesome. If you have a fairly new graphics card you should give it a go. The 360 demo should be out soon and depending on how that plays I might forgo the jittery mess which is playing it on my PC and get it for the 360.
I remember playing a multiplayer map of Unreal that had portals like Prey does and Serious Sam allowed you to run up walls, but for a game to take both of those fairly old concepts, realise their potential and take it as far as Prey does is amazing. You do have to play it to see what I mean. And as far as I can tell the only people not liking the demo are the ones who can't run it, but that's understandable.