First-person shooters are terrible with gamepads. Anyway, L4D2 runs ultra-smooth with all settings maxed on my Mac Pro, so I would expect L4D1 will be the same.
--Eric
I'll have to disagree with you on this one. It really depends on the FPS - COD, MW, Halo and L$D have been optimised for a game pad, and IMO they all play great on a 360 or PS3......