Yeah, I was a hardcore console FPS player for around 5 years, and I would never have admitted I could be bested by a keyboard/mouse. Now that I've started playing both, unless you are playing a game that is fairly slow, the mouse rules all. Even in Wolfenstein, a game that is mid-ranged on speed, I can tell my slight skills are amplified ten-fold when using a mouse over my Xbox controller.
In spite of this, I still bet I can a Halo PC player, consol to PC

.