Just my 2 cents.
I started to look at treadmills because w/ 2 kids under 3, it was hard for my wife to be able to run before 9 PM. I even looked at renting, just so I could get a higher end model and have the option of not ending up w/ a clothes hanger.
My wife has IT band problems and loves to run. I'm a cyclist and convinced her to try the bike on a $100 trainer I got on craigslist. My thought was that it was less stressful on her knees. And $100 is less than a cheap trainer. Result is that she actually doesn't mind the trainer, she can watch Tivo while on the bike, we have a way to use the bike during the off season, and she can keep up her cardio while saving her knees.
If you already have a bike, either road or mountain, it's an option.
