Microvision has built a laser HUD (heads-up display), a lightweight unit that fits above your brow and projects a see-through monochrome image onto your retina using a very, very, very low-power red laser. (Full color will have to wait for cheap green and blue lasers.) Microvision sells it as part of a system designed to superimpose schematic diagrams over machinery that's being worked on by a mechanic.
I admit that I'm not secure enough to adopt this device--I'd need to see Tom Cruise (or at least Tom Arnold) wearing one before I took the plunge--and it weighs in at $4,000, which is a bit outside my range. But cell phones were exotic and expensive when they came out, too. Then it emerged that they conferred a distinct advantage in your business--and personal life--so the rest of us dived in and penetration increased as prices plummeted.
Now, imagine continuous, large-screen (this is important--cell phone screens are fatally cramped for most applications), wireless access to e-mail, IM, your files and Google--from a professional perspective, you