Tiger,
Congrats on your acceptance. In the coming weeks, you should be receiving informational packets from each of the centers telling you about their programs. I think most of the centers have slightly different schedules, but the curriculum is the same. Having experienced any of the other regional centers, I can't really rank them. However, here's a quick run-down of what I've heard about each center:
Indy - About half the class will be there. There's a lot of bars, clubs, shopping, sports, etc., and lots of opportunities to do research with faculty members. Since the med school is based in Indy, you have all of the resources and important personnel nearby.
Fort Wayne - Very small class size (16), and I've heard that Fort Wayne students have a slightly higher average on the Step 1 exam than any of the other campuses (not sure if this is true or not). Fort Wayne doesn't have very much of a college scene. There are a few bars, very few clubs, and a decent mall. Classes are held at IPFW, which is a pretty small college (about 10.000 students total).
Bloomington - don't know very much about the center, other than it's on IU's main campus. I think there are about 24 people in each class, but I could be wrong. I'm pretty sure med students get all of the same privileges as regular IU undergrads (e.g., student basketball tickets).
West Lafayette - I've heard that they have the lowest average on the Step 1's of all of the regional campuses (although they still average above the national average). Classes are on the Purdue campus.
Gary - This center has IU's only PBL-based system (PBL = problem based learning). It's very close to Chicago, so you're only about an hour away from just about anything you can imagine. However, it is in Gary, which might not be the best place in the world to live.
Terre Haute - snowballz already commented on the Terre Haute campus.
Evansville - Don't know much about it other than classes are held on the campus of USI. I've never been to Evansville, so I have no idea what it's like.
South Bend - Classes are at Notre Dame, and med students get all of the benefits of regular undergrads (chance to buy student football tickets!). Fairly close to Chicago.
Muncie - On the campus of Ball State. Munice has one of the largest hospitals in central Indiana (Ball Memorial), but otherwise, I don't know too much about the campus. I think they use a quarter system rather than a semester system.
Sorry I can't be more specific on some of the campuses. Like I said, the informational packets you'll be receiving will have a lot more information on each campus. Nearly everyone will list Indy as their top choice, so if you really want to go there, make sure you get your form in early. Also, make sure you put some real thought into which campuses you list as your second, third, and fourth preferences. You might not get your top choice, and you don't want to be miserable at your second or third choice. In general, I think most students are pretty happy no matter where they go. Good luck, and enjoy the next few months before med school starts.