I think the Bulls can beat the Heat. I also think the Thunder have a very good chance at beating them too. I'm not convinced the Heat have the title wrapped up because they happen to be playing very well now.
I hope the Bulls can stop the Heat I just don't know if they have enough offensive weapons. The acquisition of Rip Hamilton will definetly help them out in the playoffs on offense against the Heat.
The Heat are really strong this year and extremely focused. Plus, Udonis Haslem is healthy and is going to be the X-factor they were missing from last year (due to injury). I'd put my money on them. The only other team to challenge Miami would be the Oklahoma City Thunder, but unfortunately Russel Westbrick (oops, I meant Westbrook!) is a ball hog.