I just got back from the Bahamas; we stayed in Lyford Cay (on the west end of New Providence Island - about as far from Nassau as you can get on the island), but we did go to Atlantis for a day.
As far as recommendations for restaurants outside of Atlantis, I can't recommend too many in the Paradise Island/Nassau area. Greycliff is well-known and has been around for ever. If you have a car, a drive out to Compass Point for dinner is worthwhile.
I don't know if you've ever been to Atlantis before, but Atlantis is NOT the Bahamas. It is Vegas on an island. Not that that is a bad thing necessarily, but you will not get a true Bahamas experience staying in Atlantis. Too many people, too much to do and see (yes, you read that right), and too developed.
If you have the time, there is a fast-ferry which leaves Nassau ever morning at about 8:00 am which goes to Harbor Island (returns at 4:00 pm). I highly recommend going out to Harbor Island for a day (or more).