Nowadays we pretty much take for granted that a GPS will include up-to-the-minute road maps, listings of restaurants and gas stations, turn-by-turn directions, on-the-fly rerouting, voice commands, and various trip planning features. Good ones also have voice recognition, the ability to say even street names, can recommend where to get a good price on gas, link to current data about road repairs and weather conditions, and can tie into Web sites about businesses. But it wasn't that long ago that a typical GPS didn't even have maps; you just set waypoints or recorded routes, or at best, prepared routes ahead of time on a PC and dumped them as a series of waypoints into the GPS.
And yet, even today's gee-whiz GPSes don't quite give us the guidance we'd need to be able to find an unfamiliar destination without a navigator, without a bit of luck, in most cities. The last hundred feet are fraught with difficulties, as are the hundred feet before each turn, particularly in cities where the roads come close together so it's not clear which one of the upcoming turns you're being warned about. And there's the issue of where you need to be in the left or right lane.
Some of this can be addressed with improvements in the database of roads, which is a perpetual challenge -- gathering the data of all the roads was a monumental task, so adding a little bit of data to it would be unthinkably duplicative of that challenge. But most of it needs something else that, if it didn't exist, I would imagine it nearly impossible to hope it would become available... but fortunately, it is being gathered right now. Google Streetview.
What a quantum leap it's going to be the first time someone makes a GPS that uses Streetview to not just tell you the turn is coming up, but show it to you. The actual road you're on, with the next turn (or the destination) highlighted. I've seen "maybe in ten years" stuff about augmented reality HUDs in cars to do this, but there's no reason Tomtom couldn't have a model out next month that did this. Putting it on a HUD overlaying reality is super, but really, a 6"-wide color screen on your dashboard with a Streetview image of where you are right now (thus echoing what you see out the windshield) with the next point highlighted, would be 90% of the benefit of HUD, but available with today's technology.
Surely Google has thought of this. Maybe they're planning to make Google Maps (or at least the mobile version) do this, once mobile bandwidth is adequate to streaming the images, or something. I can't wait.