I think I’ve talked about how VDI makes no financial sense once or twice before. The Register has a story on how Gartner has analysed the costs of implementing and owning VDI. Long story short: it costs as much if not more (I say much more) than buying and owning PCs. The reason to implement VDI isn’t simplified management, it isn’t reduced costs. It is the side effects of centralisation such as easier data access and stricter security.
Personally I think RDS Session Hosts (Terminal Servers) are a much more cost effective way of getting these same results, possibly with App-V to prevent application silos.