Kharon
Contributor
Sounds like you have some experience in the caribbean: I have a southwest companion pass and live on the east coast so plan to do a dive trip there soon. Where would you focus between cozumel/tulum, bahamas, turks&caicos, grand cayman, honduras, etc
Out of the places on your list I've only been to the Bahamas, Grand Cayman, and Roatan Honduras. I'd pick Bahamas if you want to see sharks and wrecks.
My Grand Cayman experience was very limited by the group I was with. The shore diving they did left me cold. The one set of boat dives was very good. @KathyV can fill you in on GC far better than I could.
My roatan experience (and that of others in my dive club) was that there are few fish, mostly smaller than anywhere else I've dove - think stoplight parrot fish about 6", and few of anything except creole wrasse. Also, the viz was poor to very poor and there was a lot of trash in the water.
I've heard that coz is almost all drift diving, which I'm not expecially fond of.
I think SW flies into Aruba. From there it's a short jump to Bonaire or Curacao. Sometimes you can find good connections and get there and back without too much travel time. Also, you clear US customs on Aruba, so the trip back is less of a hassle.
You might also want to consider Ft. Lauderdale or the keys. @Scuba_Jenny can give you tons of info about those areas.