If you're in a dorm, I imagine that any TV you have will be pretty close to your mac. In that case, I'd just save your money and plug your TV into your macbook.
My ATV works great for me because I have it plugged into my TV and surround sound system in my living room. I rooted it, installed Plex, and have been enjoying my HD content on my TV ever since. I also like being able to stream my music from my mac to my stereo system.