I don't have anything against AMD, my current Desktop is a SN25P (nf4 ultra) w/Athlon 64 X2 4200+, which I use for playing a game or two, but since i do a lot of Photoshop, Protools, etc I'd like a Core Duo. And although I reckon that AMD makes good processors, I want the "Centrino Insurance".
64 is nos so much of an issue since I don't need my lappy to have more than a gig of ram...
If you have a powerbook and want a MacBook you have some MAC software, and are familiar with OS X. Why not get, and build your own OS X notebook? ... search the internet for Maxxus (God of All Crackers) and OS X
I would build it on the Turion platform incase you want to go 64 bit in the future. You may not think you want it now but in a year and a half you will probably be thinking something different since you are already on the Windows fence.