Unfortunately, while President gets all the attention, I think that congressional elections are much more important. Too many people seem to look to the president to solve all problems, as though he were a dictator rather than head of one branch of government.
That said, I have yet to see a candidate for president that particularly impresses me. Of course, jaded and cynical as I am, it would be hard for a politician to impress me.

There's something about Ron Paul that has always struck me as off; I can't articulate it any better at the moment, and he's been in politics long enough I have no problem distrusting him without concrete reason.
Obama has earned little but scorn, there's no reason to even talk about the same re-hashed Republican candidates, Palin and Trump are jokes. Perhaps one of the less well known potential candidates might spark some of my interest, along the lines of a Gary Johnson, but there's the question of their electability and, more importantly, whether I can believe any of their supposed stances or intentions.
When it comes to presidential elections the one thing I'd most like to see is a third-party/independent candidate win. I'm not even that partial to what party or philosophy they are part of; I just want to see the political establishment shaken up and perhaps pushed into actual change, and I'd like to see that the voters aren't as strongly wedded to the Democrat/Republican dynamic as I believe they are.
Well, I suppose I should add that I'd like to see a woman and/or a non-Christian win the presidency. I don't think they'd do a better job, I'm just interested in things that break up the traditional and perhaps shock people into thinking outside the political norm.