I used to do the exact same thing re: the desktops, but as I said, I kept just popping up terminals on the screen I was on until I'd made a total mess of it. The interesting thing about gnome 3's system is that switch desktop only switches the main monitor unless you have a plugin installed, which means I now have right screen - what I'm working on now, left screen - all the other stuff (eg. email in one desktop, browser in another, music player in another). I normally have 6 or 7 open by the end of the day. Then after changing a few keyboard shortcuts, I can flip between them as needed.
The cool thing about the above is that you can drag a window into the left monitor as a sort of holding pen so you can switch the other desktop and keep that window on screen. So if something comes up in my email that needs me to check something on the web, I open the email into a new window, drag it to the right screen, then switch the left to the browser. It's a different approach, but once I was used to it I didn't want to go back. Incidentally, I came from KDE 4 which I'd used since KDE 2, with a brief spell using ION 3 which I quit when the author started acting like a dick