Biking5 days a week. I started biking to work everyday, which is about 20min each way. I have to get to work somehow, so why not get a workout out of it.
2-3 times per week. I prefer DVDs that have a good blend of cardio and weight training. My favorite DVDs are from the Get Ripped series. They last around 1 hour and boy do you get a good burn from them.