Fine, let me add that several years ago before there was GPS in every car in America I used my $5 Atlas from Wal-Mart on more road trips through some of the most random places in the Southeast. I had TeleNav on a Nextel phone when it first came out and didn't like it compared to my Atlas (and my car's odometer - which gave me the satisfaction of being able to accomplish something without a computer unlike everything else in life we now do) -- I had Verizon after that and their VZ Navigator (which saved my life on an icy road in a very unfamiliar Grand Rapids, MI once so I can't totally knock it) and now the Garmin in my wife's car.
The iPhone & Google Maps reminds me of using at Atlas. It doesn't do EVERYTHING for you but it's a nice cheat and that is the experience I prefer. I don't want Jill the Garmin computer telling me to turn here here and here and I don't need to have my GPS constantly running just so I can feel special when I pull up to the stop light with the screen clearly visible for every other low-tech person to see, just so I can know for sure I'm going the right way to the grocery store that I've been to 612x before. Honestly that's why the Garmin is in my wife's car (we did not buy it by the way, it was a gift--and no I did not upload pictures and mp3's to it; stupidest feature they could have ever included, but you know there are people out there who see that and buy that model over a lower one without those features) ...I'd be embarassed to have it visible. It's not quite as bad as the people who have dual DVD screens in their minivans so that their kids aren't bored driving the 3 miles to and from school, but it's up there, in my book. So, you said it best - it's akin to a fold out map. That's exactly what I want. Now I don't have to carry around the giant map.