I'm embarking on a journey of discovery regarding all things VDI lately. Our use case scenarios here are probably heavier than normal, and our organization's layout is definitely more WAN dependent than "normal". So we need to find out what is real, what is hype, and what (if anything) will work for us in this space.
Found a good resource here: Validated Design Resources. This is the best collection of technical docs I've found covering NetApp, VMWare, and Citrix Xen Desktop - on Cisco hardware, which seems a little bit like an odd marriage. You can tell where the funding came from.
VMWare View and PCoIP appear to have some real potential for us, especially in the graphics-intensive environments, but it remains to be seen what kind of scalability we would experience given our workloads. More to come as we learn it.