Recently, Garmin announced a series of new GPS units, some of which (Nuvi 2405 and 2505 series) use what they call "PhotoReal Junction View" - well for a little more on the subject, they also cranked out a video to explain things.
So not only do they cover 60,000 junctions across the US, through their proprietary database, but they will show you a map of where to go and the PhotoReal image in a split screen. Probably the most innovative thing is that they highlight the Highway sign that you need and dim the ones you don't; very cool.