Mitt Romney's Pick For VP Will Be?

Hard to say, really. I could see someone like Chris Christie being on the ticket, but they generally try to get some "geographical balance" so having a ticket of Massachusetts-New Jersey would probably be less effective in southern states. The others have problems of their own. Palin was one of the primary reasons that John McCain lost in 2008, plus she's only become more of a laughingstock in the time since. Perry and Bachmann proved themselves to be completely incompetent during the primaries, so they're pretty much off the list. Ron Paul is not only too far outside the mainstream but also would undoubtedly not want the job. Daniels, Huntsman and Roemer all seem to be more qualified for the job than Romney, so I doubt his ego would lead to any of them. Gingrich would never take the job, as his ego is way too big to take the second chair. Colin Powell has way too much class and dignity to get involved. Pawlenty is irrelevant these days and would add nothing to the ticket. So that leaves Rick Santorum and Marco Rubio from the choices available. Depending on how Santorum fares and what he has to say in the coming primaries he might stay in the VP race, might not. Rubio, although he has baggage of his own (like lying about his family history), would be the Republicans' only chance to even try to get a substantial hispanic vote, but at the same time the fact that he's hispanic would possibly chase some of the redneck votes away.

I notice you didn't include Herman Cain on the list. Not that he's remotely appropriate for the job, but I'd have been interested to hear some people's speculations about him.