With more and more people using their computers as the heart of their multimedia centres, not sure how well a projected keyboard would fit in there. With people operating things from the comfort of their sofa i think voice command is really the way forward :)

Yeah, true. The problems is that say your listening to some music, the computer cannot comfuze the lyrics with commands, and start wreaking havoc, so that makes it more complicated. Now, a neural interface would be nice. :P