One counter example... sort of... but more to provide some, hopefully, helpful info:
I run three systems on my desk (Win 7, Mac OS X, Mandriva Linux). I run Synergy+ on all three (server runs on Linux) although I also have a KVM for those few rare moments when Synergy is not running. I also run virtual desktops on all three systems (Win 7 - 2x3, OS X - 2x2, Linux - 2x2). I am constantly switching between systems and desktops and I do use specific desktops for specific tasks. Typically I have between 3 and 5 windows open on each desktop. Lastly, I am a system administrator and only do related scripting and programming as opposed to being a developer and constantly in a programming environment.
Certainly I run the three systems to have one of each type of desktop system I typically administer. However you can also look at the setup as having three monitors as I use all three in my non-platform specific tasks. Certainly I could run with less monitors and virtual desktops although my efficiency and organization would greatly suffer (IMHO). I find organizing virtual desktops by task extremely useful when dealing with interruptions, multiple tasks, etc. Even going down to three systems/monitors and no virtual desktops would significantly increase screen clutter and decrease efficiency. Going down to a single system with remote access to the other two and having virtual desktops would be worse yet. Of course, a single monitor/system with remote access and no virtual desktops would be a nightmare.
I know other system administrators with only single monitors but with virtual desktops. However, even they have 1 or 2 additional systems on their desk which gets designated for a current task to help reduce screen clutter and increase organization. The developers I know run multiple screens when possible regardless of the platform used.
Finally, regarding virtual desktops on Windows 7: I highly recommend the following:
- VirtuaWin (using 4.3) with plugins: VirtuaPlus, VWDesktopIcons, vwKvasdoPager (this is the must-have module), VWPreview
Of course if you are running more than 1 system on your desk: