To be honest, at this point, I basically use home++ for the powerstrip bar at the bottom. It's incredibly handy.
I've used as many as 5 screens and as few as 3. Currently, I have 4.
One the main one, I like to keep it light. I have the beautiful Widgets clock up top and icons for my most-used apps at the bottom. Only four.
to the left of that are more frequently used icons, including ones I don't want someone to see right away, like gmail, pictures, etc. On this screen, I have the power control widget at the bottom for easy toggling of wifi, bt, GPS, sync, etc. The rest of the screen is apps, except for 2 folders, one with other useful apps and one with games and dumb stuff. When I had 5 screens, these two folders had their own screens.
To the right of my main screen, I have calwidget taking up its own screen. It provides a quick and easy view of upcoming calendar events.
I just recently added the fourth to the right of calwidget, and it currently only has four shortcuts to system info (battery history, running services, etc). I created this as a sort of monitoring screen to keep an eye on system resources. Shortcuts made with bettercut.
If you've got some time, check out the thread entitled "screenshots of peoples desktops" or something like that. May give you some ideas as to what you can use the extra real-estate for.
