I've done P90x. I gained about 11 lbs in one month. It's great for the bulking!
I'd ride 30 or so miles twice a week on my bike (pedicab, dont' know if you've heard of this), so I would do plyometrics, but not the cardio.
I'd HIGHLY recommend doing plyometrics. It's fantastic. My PFTs went up about 2 or so percent. Not much, but again, it keeps you in shape, and helps out your lungs, too.
I'm going to start the routine over today. I never finished it the first time, only made it through the first month. If anyone wants to keep in contact with me, share results, etc. that'd be great!
I've quit pedicabbing for now, so I'm going to start the routine over