There are some factors that point to Florida repeating as National Champs:
1) Experience: The Florida coach and players won it all last season. The coach knows what its like to go for it all, and he has 7 players that decided not to go pro last year and return to see if they can repeat. OSU coach, Thad Matta, has never been to the Final Four before, let alone the championship game. Ohio State starts two Freshmen (Center Greg Oden and Guard Mike Conley) and has three other Freshmen who get significant playing time as back-ups. If they stayed together a couple more years, they could be dominant, but they are still developing at this point as they try to defeat an experienced defending champion.
2) Size: Ohio State starts a 7 foot center, a 6'5" forward and three guards. They bring in 6'9" and 6'8" subs. Florida starts a 6'11" center, a 6'10" forward and a 6'9" forward --- all bonafide stars. Ohio State usually gets out-bounded, which means the opponent often gets additional shots at the basket, and if Ohio State doesn't hit their first shot then that is often all they get. Ohio State's center tends to get in foul trouble -- last game, he only played 3 of the first 20 minutes due to foul trouble, and the game before that he fouled out in regulation (with OSU winning without him in overtime). If Oden is not in the game, Florida's size advantage becomes even greater. One plus for Ohio State: They are experienced with playing without Oden, as he missed several games at the start of the season due to recovering from wrist surgery . . . and when he returned he played limited minutes due to lacking stamina . . then, there is the foul trouble that has often limited his playing time.
I think Ohio State and Florida are pretty even in team speed and outside shooting prowess. Ohio State's chance to win comes from keeping Oden in the game (and, of course, his being effective while in), good minutes from back-up players, a good outside shooting night, and good team defense (forcing turnovers too). If they could turn the tables and get some Florida players in foul trouble, that would be very helpful. We shall soon see.