Definitely Nashville. Awesome city. Knoxville would be second, if you allowed me to put it on the list. Athens would probably be third. Lexington probably fourth. Most of the rest are just little sleepy towns with no great distinguishing characteristics (not that there's anything wrong with small towns, as a Tullahoma boy, I like 'em). The hell-holes are Starkville and Tuscaloosa.
Have to caveat all the above with: never been to Baton Rouge, College Station, or either of the Columbias (Mizzou or South Carolina). Well, I drove through Columbia SC on the interstate a few times, but didn't really see the city. So don't know where they'd fit.