I adore my Garmin Nuvi. I have the small model that can fit into your pocket, but I’ve heard good things about the cheaper-but-boxier model.
It’s pretty easy to use. I have run into only a few glitches with it (it didn’t know where I was, or, it freakishly had the highway drawn wrong and thought I was driving through a cornfield when I was still on the road), but those have been minor. Otherwise it’s been great. I use it locally but it’s also been a real lifesaver on vacations. It’s good not just for finding the major things (How do I get to the zoo?) but also for minor ones, like what’s the closest gas station to the airport for when I return the car rental? Where is the closest laundromat, where’s the postoffice? There are no goddamned street numbers visible here–what block am I on?
Mine has the MP3 capability and the picture viewer, but I don’t even bother with them.
I do occasionally have to tell it to shut up, as others have said. But it’s been great.