With the release of Boot Camp 1.2, which supports Windows Vista, I believe that the Apple MacBook is the best notebook that you can buy for running Windows Vista.
First of all, it has great industrial design and is full featured: a nice complement of ports, built-in DVD burner, built-in webcam, etc. Its form factor is right - nice and slim, not too heavy but substantial feeling at the same time.
Secondly, you can't really beat the software value proposition: it comes with Mac OS X and iLife and for a couple of hundred dollards, you can buy Vista.
The Vista install experience was awesome - far better than on some PCs I've tried it on. Basically, it just works. The driver disk that Boot Camp creates has everything that Vista needs and it is all installed for you by the installer - in the right order. No guessing about which .EXE to kick off first.
That's it - you end up with a fully functional Vista system that supports Aero Glass and scores 3.1 on the Windows Experience Index.