FPS cannot be played with a gamepad, you need a mouse.
i know a lot of people that can argue that, my brother especially. I hate gamepad for FPS but he loves it, even hooks up his xbox gamepad to PC to play borderlands.
i love mouse and keyboard so much less to do with your hands to get the same things done and in most cases M/K player will trump a gamepad player anytime. but again practice with either will help with skill :P