In the city centre:
Purnells – Wonderful, incredible food but not cheap and you have to book a long way in advance
The Asquith – Purnells bar that still does some amazing food
Opus – Good quality, fine dining, great service and not as popular or expensive (or arguably as good) as Purnells.
Anderson Bar and Grill – Great grill place, not overly formal but really good
Cote, Mail Box – A chain but one of the better ones and a good option if can’t get in at some of the others
Ikon Gallery – Casual tapas type dining, quite relaxed but good food
Edit.
San Carlo – Top class Italian food but not cheap.
Lasan – Indian food done a little differently, very good and very popular. They won The F Word a few years ago.