Elliptical-ize

As you can probably tell by now, I love ellipticals.  I've even used the elliptical in boots before (I was in a sporting goods store with a friend).  It burns a lot of calories and it has a lower joint impact than running.  (running also tires me out more).  Treadmills make me feel like I'm working so hard to go nowhere.  Spinning burns less calories than the elliptical and it tends to hurt my butt.  Adjusting the seat is so awkward and it rarely is ever comfortable.  While ellipticals are lower impact, it does still have an affect.  I've had days where it hurts my knees so I really should stretch more.  Sadly I do not have access to an elliptical at home so I guess I will be jogging outside.  (Hey, at least I'll get a tan)  Usually I do the elliptical for two hours but somehow I do not think I will want to jog for two hours outside every day.  I will probably have to break up my cardio throughout the day.  Jogging in the morning or evening, walking, etc,.  At least there is a playground near my house so I can use the swings.  (It is pretty good exercise if you do it long and hard enough).  I also would like to take dancing lessons or DVD dancing lessons.  It sounds like some fun cardio that would also be a useful skill.    

So what's your favorite form of cardio and why?