recent Quinnipiac Poll, he out-polled Hillary, Obama, and Edwards handily (well outside MOE). Rudy is a very serious candidate, because he's at least a threat to take NY away from Hillary. He may not be the Red State Right's perfect candidate, but they'll come out to vote against Hillary in droves. We're talking about people who use the word "Hillary," as a substitute for "Hell." As in, "What the Hillary do you think you're doing."
As far as other Repubs that might run, that aren't damaged goods, I'll offer up the name of Chuck Hagel. I think he's seriously considering a run, and will probably announce at some point. He's probably the (potential) candidate I fear the most. His foreign policy positions are, for political purposes, the same as Wes Clark's. The difference between the two, of course, is that Clark is a Liberal and Hagel is very much a Conservative. Hagel votes with Bush on everything except FP. Although he did vote for IWR, that's not going to hurt him with people who are likely to vote for him---that's an issue that only matters to a small contingent of politically active Dems.
Rudy has a certain appeal to those who are drawn to authoritarian figures, but I suspect that Hagel would beat him because of Rudy's "baggage." I think Hagel has more intrinsic appeal to "heartland" type voters. OTOH, he'll lose some ground with some Repubs because he's so outspoken against the President's Middle East policies. Between the two, Rudy's gonna get the AIPAC money. In any case, I think he'd definitely shake things up a bit.
Rudy = authoritarian, neoconservative.
Hagel = heartland conservative, and realist anti-neocon.
Stick a fork in McCain.
Check out this poll:
http://www.quinnipiac.edu/x1295.xml?ReleaseID=1019