Jonathan Bernstein does some very early analysis:
The more I think about it, the more Perry, DeMint, and Barbour appear to me to be very serious contenders, although I wouldn't rule Romney, Palin, or Huck out. Our of the second list...I can't quite see why any GOP faction picks Pawlenty over the other choices; the same basically goes for Thune, plus he has the disadvantage of votes to defend. Christie? Well, it's not quite clear yet how he plays if he's an actual candidate; truth is, he really belongs on the longshot list. As for the other three: DeMint is a clear leader of the conservative wing of the conservative party, without straying (as far as I know) into the kind of territory that gets some of the candidates he endorses into trouble. If they insist on supporting a factional candidate, and can agree on one, they may be able to pull it off, especially if Palin (whose Palin faction overlaps with the conservative faction) drops out well before Iowa. Perry and Barbour, on the other hand, appear to me to be acceptable to every faction within the party, as well as being better positioned (through fundraising potential for Perry, and good personal relationship for Barbour) to cash in on it than others.
Of course, we're also talking about a party that cheered on O'Donnell and Angle and Buck and Miller, so perhaps they'll do something totally off the wall. But that's how I see the field so far.