If you're unsure do a bit of research on the Garmin website, then go out and get the cheapest Garmin you can find. (They all have essentially the same function and interface.) If you use it, you'll quickly figure out what additional features you want. (Bluetooth, street names, traffic, etc.) Then go back to Garmin's site and you can be educated to find the exact unit and features that you will need and want. Search the internet for the best price..and viola... You've been assimilated to the GPS age. :yahoo:
You can also, go into Best Buy or your favorite electronics store and stand there and play with one. It really is amazing all thing things you can do with them now. (Road type preferences, Road avoidances, Traffic, street names, automatically reordering waypoints based on best gas mileage, etc...)
Then put your first unit on Ebay or sell it to the next person on the fence about a GPS.
I have used this method with both my and the wife's parents. Her dad was much like you, didn't see the need but didn't want to miss out on anything and he out grew his unit in about 2 hours of playing with it. He then went out and bought a more advanced unit and gave the beginner unit to his son.
I myself have a Garmin Zumo 550. I got it primarily because it is waterproof. The street names, Bluetooth, traffic and MP3 capability are also nice on the long trips. Heck I even use it in the plane in off-road mode when I fly as a 2nd GPS.