Well, obviously, most netbooks will have XP, since that is the popular software. But that's sold. Here's three key facts to remember:
1) M$ knows exactly how many activation keys they are putting out there.
2) M$ knows exactly which keys are not activated (like the one that came with Kylie, my IBM S10)
3) M$ knows which ones are not being used because they aren't phoning home anymore
Combine this with M$ offering huge discounts on XP to OEM's to put it on netbooks, and you know what? That M$ tax on Kylie because it came with XP? With all the "free" software M$ paid to put on that machine? They actually subsidized the machine, and made it more affordable. They helped put another Linux computer out there.
Thank you, M$. ;-)