I tend not to read reviews often. If there is a game I want, I will buy it. Like KH II or FF XII, regardless what the reviews said (though they were good in both cases), I bought both games without a second thought. Sometimes, on long trips I will buy a gaming magazine and have fun reading the reviews and looking at the screen caps. If something catches my attention then, I might look up the game a bit more before considering buying it.
I think probably the best source is from friends who share your taste. In things. When I am looking for a new fantasy novel, if I ask for suggestions I take those of people who I value their opinions (i.e. like similar stuff as I) than some random person. The same is with video games. Sometimes a friend will be like "Hey, I played this cool game, that I think you'll enjoy" thus I get interested and wanna buy it. Which reminds me, what was that name of the game my friend recommended a month ago? x-x;