I'm going to write this from the perspective of new mac users (of which, looking at Apple's sales figures, there must be a fair few out there by now). For these people we should never discount the kudos which goes with all things mac...
Apple sells an awful lot of units based on aesthetics alone and the status/lifechoice which is associated with owning a mac (you too can be a 'creative' and bask in the glory of your own magnificence in a coffee shop near you). This is not a bad thing. This is pretty much why I bought a mac. I liked the idea of a mac before I understood the reality of owning one. Now that I do actually own one, I'm finding out that the reality is pretty good too.
Over the last 12 months, I think a lot of people have been going into the Apple store (for lots of different reasons, but I bet a lot have been prompted by owning an iPhone) and saying, 'I've always wanted a mac, but never bought one... Hey, the MacBook looks nice, but a bit tired (remember this is pre re-boot), and hey.... this Macbook Pro 13" is not that more expensive, looks better and is pretty bloody fantastic... but wait, what about this 15" thing over here.... Oh, hang on, jesus that's expensive...'
And so it goes....
With the MacBook rebooted, I think you'll see it hitting the top of the popularity charts in about three months time just because it's cheaper. Let's face it, so many people cant afford this stuff but want this stuff. If you price it within their range, they'll bite your aluminium unibody hands off....