I used to build family and company PCs. I stopped when I realized they all expect lifetime service for free. Now my mom has a Dell, my sister has an Eee, my company has Macs, and they all have reasonably competent support organizations that aren't me.

I still roll my own though.

I imagine weapon switching working along the lines of the scrolling seen in the video. You use one hand to aim and shoot and the other for "swishing" through your weapons. Activating the sniper scope could be your arms-in-a-different-position scenario.

It's the movement I'm tripping over. Would you lean to strafe? Twist at the hip to turn? Simply nod your head to change view angle? Voice commands would be good too, for things that are trivial with mouse & keyboard but would be ridiculously difficult with full-body motion. "180!" "Rocket jump!"

Damn. Now I'm looking forward to a Natal FPS.

I honestly haven't seen a 60hz LCD for years. My four-year-old Samsungs are running at 75hz, and current nicer TVs run at 120hz.
 
/takes off pedantic hat