There are trade-offs with either. You'll miss the structural rigidity of the unibody if you go with the classic MBP, and you'll miss the screen quality of the classic MBP if you go with the uni. Make no mistake, the MacBook is not merely a 13" version of the MBP. The screen quality is inferior on MB, and you also have to deal with the (admittedly arbitrary) possibility that since the MB is a rev A product, there will be problems with it down the road. Whereas the Classic MBP issues are, at this point, well documented.
Personally, I bought the classic MBP - a refurb, no less - mainly because of the screen size and quality. I work in various lighting conditions - outdoors, bars, airports - and really need something less reflective than the glassy screen of the Uni MB. Also, I like the 15" of screen real estate. These are just my personal preferences.
