The clearest water I have ever seen was on Abacos Island in the Bahamas. A great place if you don't desire night life. You can scuba without getting certified, and renting a boat for the day and going to Turtle Cay for a picnic or Harbour Cay was fantastic. Other than that, Playa's water was just about as clear. Very calm because Cozumel blocks it off from the ocean, and some very nice places to go to around it like Xel- Ha or Xcaret. If you are at all interested, this site belongs to a friend of mine and I will vouch for him as I was with him on many of the trips. We stay at the Iberostar and have been quite impressed. There are restaurants in town, but the food at the hotel was so good we didn't eat off the grounds often.