I have been playing basketball 3x a week for about 2 hours each day...and usually try to run at least 3 miles once a week.
I also add in the elliptical 1-2x a week for 40 min, trying to burn at least 500 calories at a time.
I have a big body frame, so I'm trying to maintain muscle (until I hit my weight loss and waist goal, then I'll start more strength training), but for now, I try to do at least 25 push-ups at the top of every hour while at work, to go along with 15-20 crunches at the same interval.
I have been at it since Nov of 09 and am down about 25 lbs and 3". 255 right now, and I would like to be down to 215-220 by the end of May.