Hillary Clinton - plastic surgery no doubt. My guess a neck lift, botox, eyelift, and either a mid face lift or forehead lift.
John McCain - He was being attacked 4 years ago for looking too old so this time around he had to freshen up. To me it looks like he's done some anti aging skin laser and a little botox.
The others I don't know what they looked like before so it's hard to say. Why couldn't "Botox Kerry" have won in 2004