There's a thread running on Slashdot regarding retinal scanning displays triggered by a New York Times article.
I'd also like to see these coupled with video cameras and face recognition software. Then I could see people's names hovering over their heads. That would be the killer app for me!
But Slashdot reader "rw2" took the idea one step further in this comment:
Combine this with stereoscopic imagers and eye tracking. Now the box can map in a virtual environment everything you are seeing in 3d. The next steps are obvious. My favorite is new 'skins' for the things (read, people) around you.