With all the hype surrounding 3D desktop interfaces these days, it's always fun to take a look back at some of the projects that have helped us to get where we are now: http://research.microsoft.com/adapt/taskgallery/
I've always thought that this project was actually a pretty good idea (except for the BOB’ness of course), and probably one of the only 3D interfaces I would actually use. It's summed up pretty well in this excerpt from the site:
"People typically spend most of their time concentrating on one task at a time, whether on the computer or engaged in more tangible pursuits. This concentrated focus, though, is often interspersed with attempts to gain overall awareness of context. Sometimes this happens serially: intense focus while writing a document and then a brief and temporary switch to check email. Sometimes it happens in parallel: taking in peripheral information while driving. Current computer-based productivity applications do not support this basic need: the need to combine focus and context. By placing existing productivity applications in a 3D environment, the TaskGallery design lets the user easily and dynamically choose a balance between focus and context."