God of War 2 for sure! I've only completed God of War 1 on my PS3 so far, I would like to complete god mode as well to unlock more treasures, but that's really hard!
I don't know if you enjoy cute funny games, but I've got Ape Escape 2 and 3 as well with which I had fun playing with my girlfriend. I bought part 3 because we already finished part 2, which looks a bit more polished graphically, funnier, more varierty, but also seems a bit too much on the easy side so far. Not a hard game, so little kids will probably enjoy this as well.
I am looking for Okami myself, but I couldn't find it in any of the shops around here.