I also vote for an elliptical, if you like them. I got one a few years ago and have it in our game room. I use it ALL the time. It's often to hot to run in Houston, or raining, which is the reason that many people workout inside. I would also get up before class in basic sciences and workout (at 5am, when I don't want to go running by myself in the dark), or workout at night. I can also workout on the weekends when my husband is doing something and my kid is napping and I can't leave to go somewhere. I would vote for something that you can also studying on, like the elliptical or a bike, but if you hate those and would only like a treadmill, then go with that. Good luck!