I use Metacritic and Gamerankings - then select a few high / low reviews and scan them for consistency.
I don't always go to one site nor do I specifically favour/disfavour one site.
I find game reviewing is still somewhat of an 'immature' art so I take reviews with a pinch of salt and adjust the 'score' according to anything odd I spot - for example I saw more than one review of R&C that docked the game for lack of MP, which to me is nonsense - you review the game as it was intended to be (in this case SP only).
Simple stuff like that I see all the time, or games being docked points for being latest version but very polished while games with a lot of money behind them like Halo 3 get perfect scores for the very same stated reason - latest version but very polished!
I also try and look to previews and general internet 'feel' rather than specific reviews too.
For really innovative games I tend to dive in - like it or not I figure I want to try it and give support to developers trying new stuff. So I'll be buying LBP whatever and I bought Patapon in a second even though I was half convinced I'd hate it (I don't thankfully, I think it's great).
Try to be reasonable... its easier than you think...
