Oh yeah. I forgot about AI since this was a mostly graphics-focused thread. I've found it amazing that AI hasn't advanced much over the past decade. Most of it's fairly basic stuff. It's pretty bad with F.E.A.R. still stands head and shoulders above nearly every AAA game out there today. That game was 12 years ago, yet I haven't seen anything since that really made me take a step back and go "Whoa, that's some good AI." Maybe the closest thing to it was BioShock, whose enemies seemed to make decent use of their environment.
Don't forget Killzone 2 and S.T.A.L.K.E.R. Shadow of Chernobyl. All three games stand above all others regarding AI.
Whoops. Forgot about KZ2. I did borrow that from a friend and the Helghast AI seemed pretty competent. Haven't played Shadow of Chernobyl yet, though.