That's an awfully big question. In Florida, I usually dive in the Key Largo area. The John Pennecamp sanctuary is located there and, IMO, is the best diving in the Keys. I use Quiescence Diving Services in Key Largo. They operate only 6 pack boats, max. of six persons per boat. Many diveops will put 20+ on a boat and I do not care for that.
There are a number of wrecks along the SE side of tjhe Keys, mostly from Marithon north. My opinion is that the further south you go in the Keys, the worse the diving is. Except if you go to Key West and get on the Spree liveaboard for the trip to the Dry Tortugas. The Vandenburg is a new wreck in Key West that is neat.
There is some decent diving along the Atlantic coast north of Miami, but I'm not real familar with that and will leave that to others to opine on.