I'll never use a desktop as a personal system again, so this doesn't affect me to the same degree. And I'll continue to buy Macs as I don't see any compelling reason to ever go back to using Windows.

I do keep a self-built workstation running Windows as my PVR server, but the only thing that ever gets changed out in it anymore are hard drives. Over the past few years any time I've had to update it I've had to pretty much get rid of everything else (except the case and optical drive). Even the power supply has had to be swapped out because older ones were no longer compatible with new motherboards. In the end, the only reason to keep a desktop-type system here is so that I can use the TV-tuning add-in boards, because the HD space could just as easily live externally as NAS.