I just read about a simple, yet great, idea of how to use the virtual desktops for different purposes.
You can read about it at Lifehacker:
http://lifehacker.com/5054241/wallpaper-your-desktops-by-context
The basic idea is to have different wallpapers telling you what to do, like the following:
(quoting from Lifehacker):
"Read" - pretty self explanatory
"Write" - Blog posts, papers, etc.
"Draw" - All manner of art related activity, including photo manipulation, illustrations, etc.
"Build" - this is for programming (I'm just learning)
"Get" - for BitTorrent, file transfers, etc. (This computer is also my file server for the house)
You can see an example here:
http://flickr.com/photos/nirak/2853608773/
I think this is a great idea and it would be cool if the Ubuntu desktop was preloaded with this. It can't be that hard to implement, and you'll always have the option to turn it off.