Killzone 2 was pretty technically impressive, even if the single player campaign was pretty bland. I have to say I didn't consider enemy AI behaviour in that game to be impressive at all. I'm guessing developers involved in AI programming know more than I do on that front though, so kudos to KZ2.
I wanted to read up on the specific technical changes to the AI director 2.0 from last year, but the aigamedev site won't let me read the entire article without paying. There are some pretty impressive changes with l4d2, and it's good to see it get recognition here as well.
Still haven't played Uncharted 2 though. I just have no idea if it's any good. Maybe I'll get it once it's a platinum hit.
Demon's Souls Official Thread | Currently playing: Left 4 Dead 2, LittleBigPlanet 2, Magicka