Among the major party candidates, my favorites (so far) are Obama and Kucinich.
While they're both 100% wrong on gun control, I don't think a president can do as much damage on that as they can on foreign policy and on due process (habeius corpus, right to a genuine, speedy, and public trial, and so on).
Obama gets triple points this week for announcing that he would work toward nuclear disarmament.
And Kucinich is the subject of this interesting profile in the Chicago Tribune.