Lots of good wrecks to dive in the Keys. In Key Largo you have the the Spiegel Grove, the Duane (my fave), and the Eagle. In Marathon you have the Thunderbolt.
The Benwood is also in Key Largo and runs about 40 - 60 feet. Even on the Spiegel, the down line ties in at 65 feet and there is plenty of structure above 100 feet.
For charter, my fave in Key Largo is Blue Water Divers. They carry about 10 divers and will let you do back to back dives on the wrecks. If conditions permit, you can even do the Spiegel as a drift dive. My fave in Tavernier is Conch Republic.