With MS ending support for Win2000, a place where I sometimes work is replacing the machines that run Win2000. They are all pretty old. There is a blanket contract with Dell. There are a number of hardware choices and one may choose either WinXP or Linux as the operating system.
The establishment forbids the use of VISTA on any machine connected to the in-house network for the time being. They expect to approve of VISTA "someday" after they have verified that the main in-house applications can be made to work correctly with it.