Seriously I'm getting sick of everyone quoting them. I have yet to see a single average on that site that does justice to any game.
Honestly I trust one review and one only, IGN, the most professional of all review sites.
Grant it its nice to see someone willing to take the time to see what the average of the general consensus of reviews end up but it doesnt seem like its something to really trust as you dont get a feel for why a game got it's score. Averaging doesnt tell you the pros and cons for a game, a review aka critic does.
Really look now, The Onion is starting to review enough games that their scores will be averaged in. The Onion is nothing more then a bunch of rejects that decided to think they could pose a strong case towards something.
Do you really trust a site that averages in Play Magazine, My Gamer, Worth Playing, Yahoo Games, gameTM, and many clearly biased sites? It shouldn't be well any site that has reviewed X amount of games and gets Y amount of hits. It should be who is the most trustworthy a large amount of gamers read.
From what I can tell gamerankings = failure on credibility in all aspects.