Gonzo - Are you looking for an all inclusive resort or traditional hotel/resort.
In terms of an all inclusive I would check out Riu's and Iberostars. That being said don't necessarily pass up on many of the fantastic small hotels located in Playa. Many of these are beautiful hotels located walking distance from 5th Ave. in Playa.
I agree with Neal and would add the Bahia Principe resorts to the list as well. There are many good hotels in the area.
If you want something a bit more upscale I would take a look at the El Dorado Royale or the Secrets hotels.