I've used workspaces extensively since discovering Linux in the early 2000's. I find it rather interesting Microsoft is /finally/ introducing native, proper, workspaces.
Any time I try to explain it to someone who has never used them, they always ask me "Why would I use/want that?" and then they always jump on the multi-monitor mantra and say "Why not just get X number of screens?"
I personally have 8 workspaces configured. I use them all. I have my pager configured in 2 rows of 4 grid. My window manager is configured to 'skip' to the corresponding workspace by dragging the mouse pointer to the edge of the screen (with a configurable amount of resistance), so its as close to physical screens as it can get without the cost of buying 8 screens, video cards, plus power costs.
I've argued this in the past on Slashdot here, but I honestly don't see the appeal of physical screens. Maybe Windows people will finally 'get it' when Win9 comes out.