I usually take a look at Metacritic if I do take a look at a game before buying it. I also look at GameSpot sometimes, but that's rare, although generally speaking I do like them. I was an avid IGN reader a couple of years ago mostly when my PC was only good enough for web-browsing and I was still mostly a console gamer (roughly that's during the Dreamcast and PS2 days), but ever since a few years they've become more of a multi-entertainment review and preview web-site than anything related to gaming, although gaming is still a big part for them, I just have the feeling that they don't seem to make the good reviews and previews they used to make before, or maybe I can't remember the bad ones they did make before. I don't "hate" IGN though, I just don't have any interest about them but I occasionally watch their video reviews.
But, generally speaking I look at Metacritic and go on various discussion forums and read about the general consensus from Mr. Joe everyone, that's sufficient enough for me, and very often more detailed in description than any "professional" reviews.