Al Dawaar Restaurant at the Hyatt Regency - Dubai
It's a revolving restaurant, and since the hotel is right at the Corniche, you get views of the Gulf and the city (rather nice views overall).

The food is an international buffet, above average for some delicacies, but nothing particularly outstanding.

The service is good - competent and unobtrusive.

The best part of this restaurant's ambience is the highly eclectic dining crowd that adds a certain cultural vibe to the setting. Also, the restaurant has very low lighting and so one has to be a bit careful to make sure they return to the right table from the buffet station.