Hell yeah, he does! Like Possum Man I tend to wait for things to come down a bit in price before getting them, however my first brand new purchase in a long time has been the Orange Box, based on generally good feedback from one and all but definitely Yahtzee's review was the deciding factor.
It's not that I'm an easily impressed fanboy, but his reviews make a lot of sense and he doesn't ever hold back to spare anyone's feelings, but usually acknowledges, however grudgingly, the positives of games he reviews as well. PC Gamer & Penny Arcade are my usual points of reference- I trust their opinions as I have come to trust them more than many magazines and websites which seem to exist solely to shill the next portion of knobcheese-and-chips to the unsuspecting gamer public, I'm happy to say Yahtzee has joined the triumvirate (yeah, I know, PA is 2 guys and PCG a whole bunch of them, enough semantics) of reviewers whose opinions I actually consider before parting with my hard-earned.