The Idiot is acquiring quite a reputation amongst the English as a cool place to go for drinks and supper in St Petersburg. It's a dark cellar, quite easy to miss from the street (like a lot of St Petersburg eateries), but it is quite cheap, informal and the staff are friendly. It's a bit labyrinthine, with different corners to sit in, so you can be as sociable or unsociable as you like. You get a free vodka when you come in, and the blinis and red caviar are a must. The food comes in generous portions, so don't over order.
The Idiot is known for being popular with expats, and there were a couple of British and Americans there when we went, but most people were Russian(including some Russian tourists in St Petersburg). It's one of the most relaxing places to eat in the city and well worth visiting.