Each OS still has its uses. Any Microsoft operating system you can put in a business situation and most end-users will be happy. Unfortunately, you can't say the same for Linux as of yet.
Personally, each of my systems is dual boot with Windows XP and Slackware Linux. Working as a Systems Administrator for a mid-sized computer company I still deal with things in the field that 'must have' Windows. If it wasn't for that, I would be Linux 100%.
As someone stated above, in five years you are going to see some Linux distribution become the desktop equivalent of Windows. I'm really hoping so anyway!!
