I’m crazy about Saint Petersburg, so I’d like to give you some tips on where to go there by all means. First, you should walk in the center: along Nevsky Prospect and up to the Admiralty (the building with a stipple which used to be somehow connected with Russian navy), then turn to the right and get to Palace Square where you’ll find the Hermitage Museum and the General Headquarters (I don’t know what institution occupies that building now but it’s beautiful), and the square itself with a huge column in the middle of it is marvelous too. Then you’d go to the Neva embankment and maybe cross Palace bridge and get to Vasilievsky Island where you’ll find Rostrum Columns (they are very symbolic for the city)… There are museums which just amazed me by their beauty or/and cultural value: the aforementioned Hermitage Museum, the Russian Museum, the museum in the Peter and Paul’s Fortress which used to be a prison, and also two palaces-museums in the near-St. Petersburg towns – Pushkin and Peterhof (the towns are really worth visiting!). There are beautiful cathedrals all around the city, especially the Saviour-on-Blood (or they name it after Alexander II) and the Kazansky Cathedral (my favourites!). The most of sights are located in the center, so it’d be better for you to find accommodation there, e.g. in the hotels
Hotel "Nevsky, 22": Saint-Petersburg hotels - Russia tourism (if you like mini hotels) or
The hotel Oktyabrskaya (a big hotel). It’s good to stay there as then you are independent on transportation system and can walk in the center in the evening. Ah, and there are a lot of theatres in the center, some of them are always overcrowded with foreigners because do not require knowledge of Russian (ballet mostly) to be understood (e.g. Mariinsky theatre). And the center if full of cafes and restaurants of any kind – oh, my tummy, what a paradise for you!!...