I have four virtual desktops mapped to WinKey+{a,s,z,x}. I've used this scheme for so long that the keys are hardwired in my brain and I can switch desktops without even thinking about it. In particular, I don't care if the window manager organizes the desktops in a matrix or linearly, since I don't need a visual representation.

As an aside, my biggest gripe with Ubuntu is that they hard code the Win key to something else, which breaks my desktop switching habits.