Just to be the Yang to some people's Ying here, I wanna say I honestly have no idea how people do 60 minutes of intense cardio a day, like jogging on a treadmill.
But then again, I'm REALLY not a gym bunny at all. I hate staring at mirrors or TV or people's butts on the treadmill in front of me.
I don't think exercise has to be like that. Most of my exercise comes from either riding my bike in the summer (I ride my bike to and from work about 40 minutes combined, or just riding to the grocery store, around the neighbourhood, to friends house etc), in the Fall and early Spring I walk a lot. I do pilates videos, 30 Minute Shred (which is super popular here) two to three times a week and once a week I go to a hot yoga class. I also swim a couple times a month at an indoor pool near my house.
For me, finding a variety of fun activities to do is far more beneficial and something I can maintain. Tennis, karate whatever. You might not be able to burn as many calories as you would if you were on an eliptical for an hour but you'll be doing REAL things your body will do in real life not being on a machine.
Anyway, I don't know if I answered your cardio question, just thought I'd give my two cents on exercise