I really know how to read a map and have always had a good sense of direction, but even I will admit that a GPS is incredibly, incredibly useful.
1. Want to go someplace on a whim? Just hop in the car, input the general destination ( ie. Rocky Mountain National Park ) and GO!
2. On a road trip and need to find a local library for internet access? Punch it into the GPS. No need to get a phone book, find the address, find a map, etc.
3. Car running out of gas? Tell your GPS to find the closest gas station.
4. Emergency? The GPS can show you to the nearest hospital.
5. Groceries or shopping or restaurants? GPS can do that too.
6. Heavy Fog? GPS is your eye in the sky, and can show you how the road will curve ahead, IMO a very nice feature that has helped me more than a couple of times.
Overall, it's great because it speeds up your trips and makes life a LOT easier, and saves you time that you can spend elsewere, like relaxing.