From a technological point of view they are pretty neat have come a long way. However, if you can't read a map not much less having a driver that can will help you.
The newer systems that have larger LCD displays with maps that overlay your position, as well as were you have been and your route highlighted in there own colors, can be helpful getting around new places or just exploring.
One of the nicer unit, in my opinion, is the Garmin GPSMAP 176 (color) [http://www.garmin.com/products/gpsmap176C/
]. It features a nice large display and can have additional maps "uploaded." GPS City [http://www.gpscity.com/products/garmin/176C.html
] has these units listed for about $534.
Or one could go to the extreme and install a Dash PC [http://freshmeat.net/projects/dashpc/?topic_id=99,113,116,122,123
]. (Installed pictures @: http://www.dashpc.com/pictures.php
.) However, this is a bit more expensive and requires a lot
of installation. You can however get real-time traffic reports [http://www.dashpc.com/show_picture.php?id=119
] or the weather [http://www.dashpc.com/show_picture.php?id=118
] with the use of wireless LAN. An onboard computer system like Dash PC can also replace your radio/cd player. Using a sound card to output to your car's amp. you can play MP3, OGG, etc. and even a movie for your girlfriend.
But, you have a car that you love to drive so who cares if you take the road less traveled. What's the worse that could happen? You get a couple more hours of drive time in. (We all should be so lucky.) That is unless you have a girlfriend that doesn't enjoy going for a ride as much as you do.