I dislike every single one of them, probably Clinton the most. I was skeptical of McCain five years ago when he was everyone's favorite "maverick" and he has just proven me right. I really really don't like McCain.
I dislike Obama, too, but a bit less than the rest. He is a lot of talk but in action seems to be just as big of a panderer as the rest of them.
I'm really torn. Obama in and of himself seems better, but I'm not fond of the idea of Obama + Democrat-controlled Congress. His horde of ardent followers seems to really think he'll actually "Change" how Washington works like he's repeated over and over again (without delving too far into specifics, of course), which amuses me. However, I have learned my lesson from the Republican-controlled government for most of the past eight years. I think McCain overall may be a lesser evil.
Either way, I will be voting with a bad taste in my mouth this fall.