15" was never an option, because true portability with a small footprint are my first priorities when buying a notebook.
For everything desktop nothing beats an 8-core Mac Pro.
Last october I would have rushed out to get the current MBP 13" without hesitation. Unfortunately that dreadful FW-less unibody Macbook with its crappy display presented then was such a joke. So I went for a used white Macbook instead.
Too late for Apple, they lost my sale!
But I'm not the least surprised about the success of the Pro. With FW800 and the improved display they added a lot of functionality and thus the 13" model became a viable option even for videographers, musicians, graphic designers and photographers.
The original unibody Macbook was just fanboy/switcher fodder which has already turned into a fad...