I'm finishing up at UNC Med in a few weeks, but I thought I'd weigh in on this issue. I can sort of break it down by area:
McCauley St/campus area: lived here my first year, in a house with two other med students. Typically there are at least 3-4 houses on McCauley that have med students. The area is a bit undergrad-ish but not bad. Can't beat a five minute walk to class. Check the website,
www.chapelhillrent.com, to look for places like this.
East Chapel Hill: Meadowmont - nice but pricey. Finley Forest - ok, typical kinda ugly apartments, but good location.
Southwest Durham: at least consider something here. There are some nice, NEW apartments around Southpoint mall. You'll have about a 10 minute drive to get to the park and ride but there are back roads and traffic is never an issue. Advantages are: much more central location to Raleigh/RTP/Airport, close to shopping, most likely less expensive since it's Durham.
Carrboro: many options, the town itself has a kind of granola/Birkenstock image. They call it "the Paris of the piedmont"
Southern Village: very nice, likely a bit more expensive than most areas.
With all the above, definitely consider location, but also keep in mind that once you get to 3rd and 4th year, you'll be able to get an on-campus parking permit.
Finally - just to throw this out there - if you have a way to get a down payment together, consider buying. With interest rates so low and the likely appreciation on any house you buy, you will probably come out ahead.
My $0.02. Best of luck, UNC is a great school and I'm sure you'll enjoy it.