I use KDE3, where each desktop is indeed a different desktop, not (as with Spaces), a sectioned view into a single desktop. What frustrates me on OS X is that

I use KDE3, where each desktop is indeed a different desktop, not (as with Spaces), a sectioned view into a single desktop. What frustrates me on OS X is that even when I'm on Space 2, alt-tab still shows me apps from Space 1. I much prefer the KDE3 approach where I can tell it to only show me apps and windows from the current desktop. And if I really want to see all apps I can use Kompose, a version of Expose for KDE3, though that's rare because, like you, I use a different desktop for specific tasks, grouping the apps I need.