Well, there are people (such as myself) who actually prefer working with Windows over OS X. ;)
Not that I would ever slap down $1700 for a PC laptop if I can get a really good one for half the price already (just not as shiny).
Anyways, all in all I would buy a computer for myself, and not to impress any clients in the first place.
Personal preference is what it keeps coming down to, innit! Heh