Best island for early to mid November
 

Looking for water that is still warm enough to swim/snorkel (and I mean warm...not semi-warm!) before Thanksgiving holidays with reasonable travel times w/ reasonable airfares from DFW. I don't want to pay an additional $300-500 to avoid an 8 hour layover.

Any island will still have warm water in November (before Thanksgiving), even the Bahamas. The further south you go, the warmer the water will be but not by much. There's only going to be a few degrees F. difference in water temperature between the northern most islands vs. the southern most islands - not really enough to worry about.

You have to actually give us a dollar range for your airfare budget. We have no idea what you consider a "reasonable airfare". You've only told us you don't want "to pay an additional $300-500 to avoid an 8 hour layover" - additional over what???? That said, look at destinations you can reach non-stop as fares to those locations tend to be lower than for destinations requiring a connecting flight. From DFW that probably means the Dominican Republic, Grand Cayman, Jamaica, Puerto Rico, Cancun, Cozumel and perhaps Aruba.

Ahhh...good point about what I consider reasonable. I am looking at around airfare and hotel $1,200-1,400 pp. I have yet to find nonstop to any of the destinations I am considering.

Grand Cayman is my top pick but I am finding better deals to Punta Cana. If you have been to either of these, can you offer an opinion?

Your budget is on the low side as you are probably going to spend a minim of $500 to $600 just in airfare. That doesn't leave much for your hotel. Concentrate your search to the Dominican Republic - your travel dollar will go further there and you'll usually find lower airfares to that island. Punta Cana would be a good choice for someone with your budget.

FYI - Grand Cayman is one of the more expensive destinations in the Caribbean. It's a very nice island with excellent diving/snorkeling but save it for a time when you have a bigger budget.

Cancun is a great destination from DFW. Leave in the morning and on the beach by lunch. ;-)

If you are looking for nice and beautiful water and are considering the Dominican Republic you should check the Bayahibe region. It is only about 45 minutes drive from the airport of Punta Cana, but a totally different experience.

Here you are by the Caribbean sea, and you have the best snorkelling/diving in the country. You also have lots of other kinds of excursions and water sports in Bayahibe. Something that is really nice is Stand Up Paddle Board, which you can also combine with snorkelling if you want.

Mexico will fit your budget. However, we have found the resort pools too cool for us to swim in during November and December. The ocean temps are fine though.

We've been to Jamaica in a Nov/Dec and pool temps are fine there. If this matters to you.

I think Mexico and Jamaica are both excellent suggestions. Those two plus the DR are the ones that will most likely fit your budget.