Looks like USAir goes to SXM, PUJ, AUA. I would recommend any of these. Nice beaches, beautiful water.
In SXM, the Maho hotel is right by the airport. Nice rooms, and you can watch airplanes come in over the beach.
In PUJ, the beach resorts are nice. Some are all inclusive. I think Bavarro (SP?) is one of them?
AUA has nice beaches, casinos, just about everything.
Just depends on what you like to do.
For sitting on the beach, I like SXM, but PUJ has some nice beaches too.