;D
I worked for a company that was exclusively using Windows 2000 and never bothered to purchase Windows XP licenses. Even if they accidently got some, never left it installed on the computers... If you wanted XP, you needed to have a solid reason. What does Vista bring that is a must have for corporations? Well, if the company is taking the Windows route, then Vista is the obvious choise. I guess it may be more secure as well, but then again...
Linux is getting more desktop and office ready. So you can’t play games or install adware... company policies would prevent that anyway.