It's a toss up between the xbox controller s and the Dual Shock 2. After marathon multiplayer halo sessions, the dual shock's analog sticks feel weird not being concave. I've been playing a lot of Dynasty Warriors 4 lately, and I like the controller for that.
It's kind of hard to hit the white/black buttons on the controller s, but otherwise it's great. I don't know why sony doesn't release a ps2 controller with concave sticks.