K&B all the way (since 96), but I play genres where K&B makes more sense (city-builder, tycoon games, strategy games). You also need a monitor to see charts and smaller details.

I don't play as much FPS these days (mostly TF2 and occasional replays of HL/HL2 and expansions), but to this date I don't really understand how people play FPS games on controller (I played GoldenEye and the OG Halo at friends' homes when they came out).