We've seen quite a few next-gen nav device concepts, but none with as much potential as the Virtual Cable, from a New Jersey company called Making Virtual Solid. The system uses a laser, a set of lenses, and a moving mirror mounted in the dashboard to project a 3D route-guidance line above the road ahead, as though it's actually out in front of the driver. Besides making driving that much more like a video game, the company says mass-produced versions will cost somewhere around $400 as a factory-installed option, and can be easily interfaced with existing GPS systems.Very cool technology. If they really can add it for only $400, they have a winner. I think an after market version would sell well also.
Check out Virtual Cable's website for some videos of how it works.