I stayed at the Ellis Hotel in downtown Atlanta for 2 nights. It is right as you get off MARTA so getting there from the airport was quick and inexpensive. If you are longing for an impressive lobby then pay the price for the Ritz Carlton, across the street, but if you are hoping to save a little money, you will find the hotel to be as good as any of the high priced chains. The staff was very nice, friendly and helpful. Whenever I was in the lobby I was greeted and asked if they could provide me help. The bar/restaurant are small, but that didn't bother me because I found the staff to be very accommodating.
From the Airport take MARTA to Peachtree Center and exit at Ellis Street. There are signs in the station as to where to exit, look for Ellis Hotel.