Ike certainly had it right about the military-industrial complex. He was probably the last good Republican.
Ford wasnt bad, though he didnt last long.
Still on the not so good form of 'great' I'd say Nixon. People's opinions of nearly all politicians seems to have started to drop considerably from Watergate/Vietnam on. I know, Nixon isnt responsible for Vietnam but he did expand the war considerably when he was elected to end the war, not expand it. Plus he is sadly responsible for the annoying use of the word "gate" on every scandal no matter how small. That drives me crazy sometimes.