I would have totally agreed with you before the intel switch, but recently Apple's quality control & build quality in general has started to decline.
The Macbooks just don't feel as well made as the iBooks did and there are many many more reports of them being returned due to defects. My friend's gone through two since purchasing in November and the one he's got now has a loose fitting lid. I've noticed on all of his replacemnts an unfinished-feeling 'sharpness' to some of the edges - like something that's been roughly cut and not smoothed off afterwards (sorry i'm getting too technical here..)
I've used some Dell laptops recently and, although being pig-ugly and lacking OSX, they're good solid machines that cost considerably less than the comparable Apple offering. I'm not saying i'd choose one over a Macbook/Pro - i'm too much of a industrial design fascist - but quality isn't something Apple necessarily have as a trump card anymore.