One thing I think we can all agree on, is that any OS runs best on the hardware it runs best on.
I spent a lot of time wrestling with a perfect (or as close to perfect as I could get) install of Ubuntu on my Toshiba laptop. It went on my HP laptop without a hitch, and works flawlessly.
With respect to Windows: I encountered most of my BSOD issues on boxes I built myself (I never used cheap components, but I certainly don't design systems for a living), and with older versions of the OS. FWIW, during that time, I used AMD processors exclusively. A factor? Who knows.
More recently, all of my Windows machines have Intel based Gateway desktops, or, as I mentioned, Toshiba and HP laptops. I can't say that I've seen more than 1 BSOD between all of these machines in all the time I've owned them.
Windows is a fine OS, when you consider the variation of hardware it runs on, drivers thrown at it, and users/home system builders.
As I started out saying though, I think the right hardware in the hands of someone that's not heck-bent on breaking it, is key to the stability of any OS. My next machine will be another Mac, just because I prefer the user experience, not because I have any animosity toward Windows.
Mark