Re: I've never been convinced
On the storage point, fast storage has actually become quite easy to address, largely due to SSD technology and some of the clever software solutions out there (Atlantis and VMware VSAN spring to mind).
VDI actually improves management and control - using template deployed desktops, particularly in the Linked Clone/non-persistent type approach makes maintenance and security much easier - more so in a zero/thin client estate. Managing disparate desktops and laptops, each requiring regular feeding and watering with OS and application patches and AV, all the while distancing themselves from the initial configuration is always going to be much more painful, even with products like SCCM etc to help. Of course, in a smaller environment man handling lots of old fashioned thick clients is less of a problem, but scale it up...
I agree that it's not the right fit in all cases (what solution is?), but it can be used to solve some really serious issues in increasing varieties of use cases. But I'd add this - If a salesman tries to tell you it'll save you money - smile politely, then kick his sorry ass out of the door!