mouse/keyboard
I avoid console FPSs as much as possible because I hate joystick aim to the core of my being. I only play Halo when I absolutely have to (nearly every bachelor party I've ever been to was a Halo party, because my friends are all nerds, so I submit out of respect).
Halo is made even more complicated by the fact that I have to play with an inverted Y-axis, which hardly anyone does, so I always have to make a new character and do that, then when it's time to switch out to let someone else play, they're like wtf my controls are .sdrawkcab
It's also boring.