My take on the subject.  Many of Americans think anyone from New York is an elitist liberal.  If one looks back at  Giuliani's political track record, it comes across as definitely being more from the liberal/Democratic side.  The tide of popularity he rode after 9/11 has been greatly eroded.  Stories of corruptions, mismanagement, outright fabrications and such have tarnished that polished reputation.

Many of the die hard Republicans around here cannot tolerate Giuliani because of his past and his politics.  He only switched to being a Republican because he realized Hillary Clinton was going to be using New York as her jumping board.  From an independent view, none of the Republicans are strong enough candidates.

While I do agree with many of Ron Paul's ideas, he comes across as too rabid for most voters to view him as a serious alternative.