The Witchery is probably my favourite restaurant in Edinburgh (although I've been to 'The Ivy of the North' more often...). Both food and service are as good as you're going to get in Edinburgh. Personally I prefer to be in the main room which I think they call "the conservatory" or "the garden room" or something like that. It's entirely candlelit and beautiful. They have smaller rooms (which can be hired privately I believe) which are still very nice wood-panelled affairs, but I think the "theatre" of the main room is unbeatable.