Its not just about "legacy applications"
But more about the cost of replacing a perfectly working PC to one which will run Windows 7.
Microsoft spun out a public beta of its Enterprise Desktop Virtualisation (MED-V) 2.0 software yesterday. The company said that large businesses could migrate from Windows XP to Windows 7 in a virtualised hen house using the MED-V tool. It might be expected the tool works for Windows Vista - it's just that we can't find any …
Med-v allows central management of the XP environment rather than XP mode that is individual XP installs.
E.g with Med-v you can update the XP application on your main image, then all workstations will pick up the changes next time them turn on. You can also manage which users see what icons etc...