I have Halo 3, got it as a bundle-package with my Xbox360. I wouldn't poke it with a stick though, it's just overrated mediocre drizzle in my eyes.
It's not the control scheme either, a joypad is inferior obviously (stop kidding yourself that you like it because it's harder people - the games are already stupidified to make them less hard, eg the horribly intrusive auto-aim in all Halo games, and enemies that just durrrrr around before finally taking a shot)
It's just that the game itself is really quite bad on the actual FPS part - although it has excellent multiplayer support and was great fun to play around the first Halo, when vehicles in coop were still new and fresh.
The only reason to play an FPS with a joypad is for the relaxation and hanging-back factor, which is why I actually played Bioshock on my PC with an Xbox pad. Sitting back with a beer in a comfy chair! Bioshock is not a thoroughbred FPS though, and its control scheme is brilliant, so yeah.