I have just discovered 3ddesktop in the Ubuntu apt repositories.
It gives a wholesome 3D experience to virtual desktop switching that is not unlike (or in fact if you enable the right options in the config files, exactly like) the fast user switch in OSX
Only those with functional hardware 3D need bother to check it out, but I'd just thought I'd share.
As well as being a bit of eye candy it actually serves a useful purpose to me. Often I forget which virtual desktop I left one of the many apps I tend to have open and so end up switching through all of them. I know there is a setting somewhere to allow the taskbar in gnome to show all open apps. but with so many open it gets too cluttered.
It's hard to describe but with this you get a pretty good idea of what's on all (4 in my case) desktops because they are like panes of glass in that you can see the contents from behind.