I'll try to be helpful.
One of the best tours I have ever taken in the PDC area (other than with Anna who tops the list) has to have been the Dune Buggy Tour on Cozumel. You can get more info here:
http://www.travelnotes.cc/cozumel/tours/dunebuggy.php
Our wedding party took this tour in 2002 and it was a blast. Highlights included a great dune buggy ride through uncharted cozumel (ok, maybe it's charted, but it is off the beaten path). Mayan Ruins, cook out on a deserted, pristine beach, snorkeling, and all the beer you could drink (soft drinks too).