The press is awash in speculation about whether New York mayor Michael Bloomberg intends to run for President as an independent, or perhaps on a third-party ticket; the National Edition of today's New York Times has two stories on the front page. (The website gives it somewhat less prominence.)
Let's remember something basic: Bloomberg is not going to be the next President. Even if he went back to the Democratic Party--which he bolted to get the Repubs' nomination for mayor in 2001--he would not stand a chance of obtaining the nomination, and he isn't going to win the White House as a third-party candidate, either; think Ross Perot, who got less than 20 percent of the vote in 1992.
So, the Mayor's only role would be as a spoiler and, given his positions on issues like abortion, gay marriage and gun control, his candidacy would aid the Repubs. Given those positions, there's no logical reason why Bloomberg should run. So, if he does enter the race, it's a matter of ego winning out over good sense.
(I haven't seen much of him--not living in New York any more, thanks be to G_d--but the Mayor seems like a sensible man. Still, no self-made billionaire can be short in the ego department.)