I initially thought IGN was the slimiest of the big game-reviewing websites, and while I still hate IGN, I think GameSpot is easily the worst.
I say they're easily the worst because they fired their Editorial Director Jeff Gerstmann in 2007 for posting a fair, I repeat, fair review of Kane & Lynch. GameSpot tries to defend their decision to fire Gerstmann over the fact that Eidos (Kane & Lynch publisher) was pouring a lot of advertising money into GameSpot, and was supposedly pressured to fire Gerstmann. This is a fine example of the old addage "money talks and bullshit walks," because this just tells game critics in the business that they HAVE to bend a certain way if a game publisher has fiscal involvement with the company in question.
I love to write reviews as a hobby, but after seeing what Gerstmann went through, I'll never pursue a career writing reviews for media, especially if it's with GameSpot.