Gerald Seib nails it with this statement in Pawlenty's Moment May Have Arrived:
He isn't loved passionately by any of the important factions in the Republican party, but he's acceptable to all of them.
That is Pawlenty in a nutshell. Few Republicans dislike Palwenty so he has a leg up on Romney, Paul, Palin and Gingrich, all who have certain segments of the party who actively dislike them (or in Newt's case pretty much the whole party doesn't like him). He is also few people's favorite, kind of the perpetual bridesmaid. "So and so is my first choice but if they don't win, Pawlenty would be OK". With Romney stuck in neutral, Newt shooting himself in the foot again and again, Huckabee out, no one else imminently getting in and most especially with Mitch Daniels not running, this is his time to grab some attention. The Daniels decision is huge because I think they draw from the same pool of supporters. If Pawlenty can get Daniels, Christy, Barbour and other GOP governors to rally around he might just pull this off.
His big challenge is getting to the point of being a number one choice for people rather than an acceptable runner-up. As Seib points out, he is not a fiery guy and looks a bit silly when he tries to be. His campaign announcement video on YouTube is a prime example, it was good but he sounded like he was trying too hard sometimes. Now, if you paired him with Hermann Cain as his running mate, someone who could whip up the troops and let Pawlenty be the quietly capable and professional leader, that might be a great combo. We will see.
One other thing. Drop the T-Paw thing, it sounds silly when applied to a dorky white guy from Minnesota.