You forgot Gravel and Keyes.
I favor Ron Paul, but I can completely understand people not liking him because of the aggressiveness of his supporters and such. But overall I think he has the positions that match mine; Gravel is my second choice.
The reasons I don't like the others mentioned are:
Hillary Clinton - I see her as a power-seeker with no principles, especially because she used to be a Republican and switched to a Democrat in later life, because of countless things like this
, and because of which groups fund her. She's also the most pro-censorship of videogames of any of the candidates, introducing that bill with Lieberman to mandate ESRB ratings for all games, which if it passed would basically put indie games out of business because few of us can afford to rate our games with the ESRB (it costs thousands of dollars).
John Edwards - He's too religious for me, I read that he once claimed to be possessed by the departed spirit of one of his dead clients during a trial. But I like him better than Clinton or Obama because he's more aggressively anti-corporate.
Barack Obama - I don't like him because he tries to appeal mainly on charisma and hope and change rather than mentioning anything substantial; if you've ever watched one of his speeches at a rally you probably know what I mean. I once described him like this: if someone was a foreigner who didn't know English, and listened to all the candidates speak, they'd like Obama the best, just because the way he says things. But I like him better than Hillary because he's less of a 'party man' (in the sense of a political party, not social partying).
Rudy Giuliani - I actually agree with a lot of his positions (except the war on terror), but his personality and corruption irks me so much that I'd prefer anyone else except Huckabee or Keyes over him. He also has a terrible "freedom means authority" quote.
Mike Huckabee - Wants to amend the constitution to make it say that the Bible takes precedence over the constitution.
John McCain - I like his honesty but he's extremely unstable, he's known for having a temper, for being superstitious, and for singing "Bomb bomb bomb, bomb bomb Iran" and telling people to get a life if they were offended by it.
Mitt Romney - Much like Hillary I think he changes his positions to gain power rather than having any principles.
As for more on why I like the ones I do:
Ron Paul - I'm a libertarian so my liking for him is natural. But more specifically, it was incredible that he mentioned (on live television no less) that the US used the CIA to cause a coup in Iran in the 50s, and gave Saddam chemical weapons to use on the Iranians during the Iraq-Iran war; no other candidate would dare even admit such a thing. He also said he'd pardon everyone in jail for non-violent drug crimes (like marijuana use/possession and so on). Also his campaign has led to a lot of people becoming politically active for the first time, in creative ways
Mike Gravel - Ended the draft during Vietnam and personally put his career and life at risk to do so. And things like this
take courage. He also favors direct democracy, where people personally can write and vote on laws, rather than leaving it up to Congress, which I think shows a good-hearted trust of the people.