Unfortunately, I'm not too familiar with Marietta. It's not that far from Atlanta and I've been through it few times on my way to Columbus, GA and several trips to Fla but that's about it. But it's a pretty large school, I'd be surprised if it was a dead-spot with any provider.
I can tell you after looking at the licenses that Sprint, Cingular, and Verizon all provide service to the area. Considering the size of Marietta and the school, I do believe you'd be safe with any of those. T-Mobile also does, but I've not heard great reviews of T-Mobile in many parts of Georgia. But if you're already with T-Mobile, you could try using them in that area and see how they do. That might save you from having to get a new phone, a plan with fewer minutes with another carrier, etc. if you're interested in holding onto T-Mobile. Southern Linc also serves the area, but I probably wouldn't go with a local carrier if you're in school and going to be doing a lot of traveling.
Maybe somebody else can throw in their cell reception experience from the area and be a little more detailed than I'm able to be. Good luck though. Also, if you'll be traveling back to your current location a lot, you might want to consider what carriers work well and what carriers work poorly there. But you probably already know all about that.
edit: going back and reading through the thread, if you're looking to switch to get the Q and don't want to stay with T-Mobile, I think you'd be fine with Sprint or Verizon. Sprint will give nights at 7 pm and that might help you out being a college student though.