IGN is my most trusted. They are knowledgable and fairly consistant considering how big they are. I trust IGN more than any other source. If IGN rates a game over 9.0, then I know there is some quality to the game.
GameSpot is decent. Though I disagree with many of their reviews. I dont like the way they only do solid numbers like 8.0 or 8.5. With so many games being released, I think that .1 can make a big difference in ranking and comparing games.
GamePro is probably the WORST. IIRC they gave Ninja Blade a 5/5. LOL. They give 5/5's waaayyy too easily for them to be trusted.
MetaCritic I dont believe in at all. They use reviews from sources that nobodys ever heard of before. Anyone can make a video game site, and apparently you're credible enough to be included in MetaCritics rating system as long as you know how to create a website.
"I don't have time to play video games anymore, but if I did, I would definitely choose the PlayStation 3 instead of the 360" - President Barack Obama