I run crysis on full settings @ 1920 res, no lag at all. I like crysis a lot and there is an in depth storyline, however my buddy is trying to get my to play fall out 3, i'll probably pick it up over the weekend.
what i do have to say about crysis multiplayer system it is really really cool, as far as building up to nuclear weapons and fly helicopters into your enemy. it's a very unique experience from anything i've everplayed.
also it doesn't take much to run crysis with very high settings anymore. you can do it on a geforce 9800 gtx 1gb 4gb ram and quad core processor.
Personally, the VATS and difficulty wasn't what made me love Fallout 3. The absolute sheer amount of exploration you can do is just outstanding. So many people/things you can interact with as well.