When we go as a family, we stay at The Wyndham (The Reef Club). It is all inclusive and Sand Dollar (on site dive shop) is excellent. It runs roughly $900 for seven nights, all meals and drinks, and 10 dives. It is south of town and requires a cab to town.
For our guys only dive, we stay at the Barracuda Hotel. It is just a basic, plain hotel room. For about $600, you get seven nights and 15 dives. It is two to three blocks from the main square and we get breakfast/ lunch at the Megaplex across the street.
A friend stayed at Fieasta Americana and really liked it. I do not have a price, but it is further south than the Barracuda and would probably require a cab to town.
I also think it is worth taking a day and driving all the way around the island. There is only one road that goes all the way around, you cannot get lost. They also do not drive on the island in the same manner as the mainland.