metacritic! It lists all games, movies, books.. It doesn't review itself, but it gathers all legit reviews and lists them, with a link. Then it's presented with an averaged score. I find the user reviews are just as useful.
Gamespot.com was considered alright in it's day, but with the matters now facing them, concerning the separation of review and advertiser, I wouldn't be so trigger-happy in recommended them these days.
I personally use http://www.gamerevolution.com . At times, they may seem a little unprofessional and they also have, what other review sites deem, an awkward rating system, but I find that quite often, how they right something from a game is dead-on to what I would have called it.