Sticking with my lifetime...
Walter Mondale
George H.W. Bush
Otherwise, I think the Presidents were better than the VPs. Though in some cases, it would be close -- like Gore or Rockefeller.
What about VP candidates who would have made better Presidents than their counterpart at the top of the ticket?
The best known is probably Lloyd Bentsen. Can't think of any others, as I preferred Kerry to Edwards, Bush to Quayle, Dole to Kemp and etc.
I preferred Edwards to Kerry, Bentsen to Dukakis, Bush to Reagan, and Johnson to Kennedy, since 1960.
