Well, GPS navigation has been out for a while, but it had its ups and downs. Today, it's almost incredible with which accuracy they can navigate you - whether you're going on foot, motorcycle or in car.
Most of them aren't that costy, come with downloadable maps and can be used even on your cellphones. I find it really useful as I travel a lot and I'm going to recommend Garmin as the top one. Not everyone will agree, but for my money I'm pretty satisfied with their product. I wonder what will the navigation look like in future and can't really wait for it :)
More info about Garmin :