If I had to vote for someone whose political affiliation is opposite from my own, I would pick John McCain, hands down. He strikes me as an honest, straight-talking fellow, and has demonstrated a willingness to cross party lines (and to cross party bosses), and overall strikes me as a man of integrity and intelligence.
If we could vote in both primaries, I'd back Barack in the Democratic Party and McCain in the GOP.
Despite his socially liberal history on civil unions, as well as his record on support for immigrants, legal and illegal, and on teaching evolution in public schools, Giuliani is someone I couldn't vote for because of what he did while he was mayor in New York.
He did do a lot to clean up New York City and Times Square, to curb crime, and all that was great, but he was too willing to look the other way on police brutality, stood in opposition not just personally but politically to a museum when it had a painting he found offensive (he ordered its city funding cut), and pushed other policies that, in my opinion, were detrimental to individual rights in the name of "security" and "law and order."
(I'm thinking specificaly of his desire to seize vehicles of those who couldn't be convicted of DWI, even though they were *really* guilty in the eyes of the prosecutor. Gee, that'd be, roughly, everyone charged?) All bad precedents for someone aspiring to be commander in chief.
Not to mention that he's been a one-issue candidate so far, playing the 9-11 card for everything he could, as well as the odd cell phone fetish he's displayed.