Here is a thought I had whilst watching one of the HUBB-DVD's, given you can log current GPS position, and navigate a route, how much work do you think it will be to have a "direct distance to waypoint" function? Meaning that you can enter a waypoint and it shows you how far you are from that point as the crow flies.
This is great if you are on some outskirts of a country you have never been exploring roads you have never seen or been on, yet you know how far the next town is if all goes badly wrong.
I like plain old paper maps 