I'm glad aldo pointed that one out before I did. That monster is nothing new, it was previewed for the Unreal3 engine on the PC some time ago. Saying that Gears of War is XB360 exclusive is all good and well, but the engine was still originally developed with the PC in mind. All in all - it's no reason to get too excited right now. This is nothing strides ahead of what we've seen coming already.
Not that I'm trying to put a downer on the thing, but I'd rather one of these games followed through with gameplay and storyline now. What we've seen is a lot of what amounts to a tech demo - excellent lighting, shadows, models and textures - but nothing of any real substance just yet.