Ok so this is just my personal thoughts about games taht were being demo'd at PAX '09 this weekened.
Call of Duty: Modern Warfare 2- It was like there was like nothing had changed. Oh wait there was no MW2 demo there
God of War 3- Yes. Thats all I can say about that.
Darksiders- Ok so this one looks super cool and handles really well but..... I was getting bored with it even before I finished the demo for it
Left For Dead 2- If you liked the first one buy this one and if you didnt buy the first one still get it. It's not that different from the first one. And now you can wield a sword as a melee weapon
Battle Field Bad Company 2: Ok so this one really surprised me. I have played the first one and I thought it was ok. Not bad, not really good but ok. But Battle Field Bad Company 2, that game was so much f*cking fun to play. 100% get it
Halo ODST: This was cool. We were able to play 15 minutes of the wave of enemy's attacking mode (cant remember what its called at the moment) and the action was intense. It was wierd to get use to not be a all powerful spartan warrior. And the pistol is basically the same pistol from Halo 1, with zoom and all
Hmm what else did I play there...
World of Warcraft: Caticlysim
WET
Diablo 3
F.E.A.R 2
Borderlands
Bioshock 2
Mass Effect 2
Brink
Starcraft 2
Yeah there was probably more but I can't remember right now.