You really shouldn't go with what reviews say. Watch a video, talk to a friend who's opinion you trust when it comes to that particular genre of games, use the "Eeny, meeny, miny, moe" method, but don't judge games solely by their rating. If you're going to look at a review, at least look at what the critic is saying and keep in mind where it's coming from, rather than looking at the games score.
If we're talking about which reviews are the most unbiased, I guess I'm going with Famitsū, GameFAQs, MobyGames, and 1up... maybe yahtzee, penny arcade or amazon, depending on the type of game.
However, some critics have review gauge that works like the speedometer in Big Rigs Over the Road Racing. GameSpot comes to mind. So be mindful of that.
Just in case you wanted to see what critic review gauge looks like, check the bottom right corner of the screen.
http://www.youtube.com/watch?v=mpe2JrsbW9I
