Obama by a mile. Best president since LBJ.
Interestingly, Obama is probably the most similar president on this list to Johnson - his political power was almost entirely driven by personality, surrounded himself with fanatic loyalists, and left the party completely hollowed out by the end of his second term
I think Dubya was the most like LBJ to be honest and this is without the fact that both were from Texas and both presided over unpopular wars. Obama's Presidency was more of a Democratic version of the Nixon/Ford years minus the scandal.
Dubya = JFK/LBJ
Obama = Nixon/Ford
McCain = Humphrey
Dubya, like Kennedy, won a close election that some felt was stolen and a shocking event got the incumbent re-elected in the next election.