Also, the gamespot fan reviews have Riddick at an 8.9 and HL2 at a 9.4.
I really don't trust any review sites. I avoid Gamespot because their cookie checkpoint is blocked by my host file and I don't care enough to fix it as I can find other ways in if necessary. I never found myself agreeing with them too much.
I read IGN the most, if only because the site is easily the best designed. It allows you to get access to all their new reviews for all systems quickly and easily, though it irks me that the Blockbuster ad always cuts the second paragraph in half (my system only maybe?) I actually agree with them less than most others, but unlike movies I haven't found any review sources for games I genuinely trust. Hell, I was flipping through Xbox magazine and they gave the new Goldeneye an 8.0 and Fight Club a 6.4 and I consider those two of the worst games I've played all year.
I use reviews not for the rating but to see what they like and dislike. If they like things I don't care about I don't bother, and if they dislike things I know would irk me I don't bother.