There's certainly plenty of good London recommendations on this board, but let me please add my specific request:
I need a recommendation for a great restaurant where I can get a reservation on short notice. I'll be staying at One Aldwych on Tuesday night (tomorrow!) and did not make plans in advance. Location is unimportant: convenience to One Aldwych would be nice, but I certainly don't mind traveling. Cost is not a consideration, but that doesn't mean that recommendations should be limited to the most expensive places.