Unless you’re in a contested state you should vote for a 3rd party candidate. There should be a Libertarian Right candidate (called “Libertarian”) running that you can vote for.
If you’re in a contested state you should vote for Clinton, since at least she’s not intimately tied to the Neoconservatives. She’ll be much less likely to greatly destabilize the world and she’ll probably manage to avoid bankrupting the country, two things I can’t say with any confidence about Giuliani.
Giuliani will provide an extension of the Bush policy in all respects. A further hollowing out of the American economy by transferring trillions of dollars from taxpayers to a small corporate elite, perpetual war in the Middle East (certainly against Iran), likely terrorist strikes (probably multiple) on U.S. soil. Throughout it all he’ll assure us he’s fighting the “War on Terror” and present us with cool techno gadget systems like COMSTAT that he wants us to believe are doing just that. Meanwhile, terrorism worldwide will increase while the American media reports the latest success against Al Qaeda. Islamic Fundamentalism sees increasing growth in American-dominated countries like Afghanistan, Iraq, and (probably) Iran while mysteriously it sees no such growth in the absence of U.S troops. The media will assure us that this growth requires American troops to promote democracy and the cycle perpetuates ad corpsenum.
If we get lucky Giuliani will receive a rifle shot to the head, killing him instantly. If we’re not lucky (as we never seem to be here in the United States of Amnesia) Giuliani will have a “successful” presidential term and have the political machinery necessary to roll up a 2nd term.