Installed Windows 7 Ultimate N today on a MacBook from 2007 (the white one).
1. Booting from a "normal" Windows 7 DVD would just give me a message saying "Select CD-ROM Boot Type". The solution to this can be found here.
2. Installing the Bootcamp drivers for Windows from a Snow Leopard DVD wouldn't work, it would always tell me that it can't run under x64. Bullcrap. It can run. Here or here is how.