I'm a little surprised people are so ready to give this one to McCollum (although I'm not from Florida so maybe I'm missing something here.)
McCollum is a bit of a perennial candidate who has lost several statewide races. Alex Sink was the Democrats' top tier recruit and has a great geographic base for a Florida Democrat. Plus, Republicans have controlled the Florida governors' mansion for 12 years and in a closely-divided state like Florida, I'd imagine that the pendulum effect would favor the Dems somewhat.
I imagine it'll be close, but I think a Sink victory is very possible.
(And no, I'm not being a pro-Dem hack. I think Republicans are very likely to pick up governorships in New Jersey and Virginia (this year) and Tennessee, Michigan, Wisconsin and Pennsylvania, for example, as well as having decent shots in Iowa and even Massachusetts and Maryland.)
Sink, could win. But McCollum has been up in several polls. He also has name recognition and has most of the party behind him (so does Sink). The race will tighten, but I think in the end McCollum will be victorious, well I hope.
Latest poll has McCollum leading Sink 43-34.
McCollum has a definite early lead, the poll also said that Crist has 67 approval ratings.
Florida is by default a Republican state, IMO. Democrats have to work hard even at state level.