Damn, you've been unlucky! I only recently upgraded to a MacBook Pro 17", which I bought second hand off eBay. No problems with it so far. The PBG4 17 it replaced is still going strong in the not so gentle hands of SWMBO.
Hey! On the bright side, maybe with all this bad luck, you're getting your lifetime's quota out of the way in one go. Time for things to get better!?