At first I wanted to recommend a bigger tank, as a 10 gallon doesn't allow much room for plants or aquascaping, especially after adding substrate.
Then the issues with frequent moves was pointed out...
So, yeah, maybe a 10 gallon or even smaller would be good for a dorm setup. Also, a tank that size or smaller can probably just be set on a desk/dresser, and won't need a dedicated stand like a larger tank may.
I had my first aquariums in college as well.
I'm thinking that the suggestions made above, a small shrimp tank, mostly moss, fern, and anubias might be pretty good. durable plants that don't require much, and they won't need a deep substrate either, so you won't loose as much room in your tank.