I have stayed at the Westin in downtown Atlanta, and it is very nice. Typical hotels like the Ritz Carlton (in several locations, including Buckhead) and the W Hotel are very nice.
If you ever visit Orlando, Memphis, or Little Rock, you have to check out the Peabody Hotel. It is the ONE hotel that I have always wanted to stay - they have ducks in the lobby! It's very cool. check out: http://www.peabodyhotelgroup.com