Personally I think the whole idea of a 3D world as a productivity environment is silly anyway. It's the sort of thing that looks totally awesome in fiction but in reality, well... short of being able to sever the spinal cord and insert some sort of peripheral interface which substitutes for the body *exactly* there will always be massive user interface issues. (Even severing the spinal cord wouldn't be enough, really. What about synchronizing the visual input with, say, proper inner ear sensations? The reason people used to hurl or get migraines after playing their Virtualboys for more then an hour is the brain resents it when the various sensors it uses to coordinate motion and balance return conflicting information.)

I guess from a broader point of view I fail to see the productivity to be gained by interacting with virtual doppelgangers of productivity tools instead of actual productivity tools. If I sit my avatar down at a virtual computer to type an email (I suppose I'm waving my virtual fingers in the air as I'm doing this) am I going to type any faster then if I were actually sitting down at a real keyboard and typing on it? The virtual computer might look all cool and Matrix-y and impossible to build in real life, but the real life computer rendering it is wasting gigaflops of CPU power and kilowatts of electricity compared to the simple VT-100 terminal that would let me type the email equally well. ;^b

Of course, if I can play Worlds of Worlds Of Warcraft then it's all worth it.