DeKalb - Heavy Democratic.
Fulton - Split. Southern half is city of Atlanta, heavy Democrat. Nothern part is heavier Republican.
Cobb - This would be a more “Georgia/Southern Democrat” county. I suspect it will be mostly Republican in the presidential election, but will have a large percentage of Democrats.
Gwinnett - Heavily Republican (John Linder district.)
Henry - Not really sure, has elected a Republican congressman, but south of Atlanta has been more Democratic historically.
Actually Cobb is heavily GOP. The only Democratic area is S. Cobb which is definetly more of the Obama than "southern Democrat" variety. 4 of the 5 county board members are Republican and two of the three U.S. House delegation is Republican as well. McCain will take Cobb with 55%+. That much I can guarantee.