Westin Peachtree Plaza in downtown Atlanta. This is a high rise about 72 floors with a revolving restaurant on the top floor. It is within walking to all the attractions that you mentioned.
The property is rather in need of an update, but it is convenient to all the locations you wanted to visit. One thing to know, there is not much activities around the hotel after dark. There are restaurants around the hotel, but you do not have many choices.