For some reason I see the Heat beating the Spurs in the finals. It'll take Lebron raising his level of play to godly levels which I think he's capable of. Plus the whole coming full circle thing of Lebron beating the team that handed him his first finals defeat.
If they don't have Bosh they won't have a chance, but with Bosh I think they stand the best chance of anyone to beat the Spurs. Their small lineup is much better on both sides of the ball than the Thunder, and with Bosh it could pull Duncan out of the paint when they go small.