NYC's ex-mayor against NYC's outgoing mayor against NY's senator.
It could happen. Giuliani is the Republican front runner (cough, cough), Hillary is the Democratic front runner, and Bloomberg is this close to running as a third candidate with as much moola as a normal main party candidate would have:
New York Mayor Michael R. Bloomberg is prepared to spend an unprecedented $1 billion of his own $5.5 billion personal fortune for a third-party presidential campaign, personal friends of the mayor tell The Washington Times. "Bloomberg is H. Ross Perot on steroids," said former Federal Election Commission Chairman Michael Toner. "He could turn the political landscape of this election upside down, spend as much money as he wanted and proceed directly to the general election. He would have resources to hire an army of petition-gatherers in those states where thousands of petitions are required to qualify a third-party presidential candidate to be on the ballot." "If Bloomberg runs, he could have more money on hand than either of the two major party nominees," said Mr. Toner, the former FEC chairman. "It would be the first time that happened in the modern era." [Link]
[Oh, just to clarify, I'm not saying that these are the best candidates, I'm just saying it would be fun to see this race]