I tend to do two things before buying most games - I focus on video reviews (written reviews of a visual medium feels like a job only half done IMO) and I watch a lot of them. But I also know who's to believe and who's to take with a grain of salt. Rank your trusted sources for video game reviews.
Mine generally goes like this: 1. Zero Punctuation 2. Giant Bomb 3. Gamespot 4. Gametrailers 5. IGN
I used X because I don't give a rat ass about ranking my people. If they weigh in on a game I'm thinking of, I'm hearing what they say to see what their take on it is. They have tastes similar enough to mine to do so.
i like igns layout better so i go there sometimes for gaming news. i never look at their reviews though. id give some respect for gamespot for being the only honest review site when they reviewed zelda skyward sword. i think they were the only site that actually played the game and reviewed it objectively rather then giving it a 10 before even playing it because its zelda. they were the only accurate review i read on the game.
dont even know of the others aside from gamer reviews from individuals on youtube