who else is still on XP - and I mean a LOT of XP

My company has about 200 desktops running XP Home edition of about 250 desktop, As you can imagine this is a detrimental blow to me finally adding an Activer Directory Domain Controller. We are having to bite the bullet and replace all of the desktops with new HP units that are running Windows 7 PRO. My users are getting a forced upgrade as our company needs to enter the current day and age.