Of course Google Maps has changed GPS usage forever. http://goo.gl/aUY7pZ
Add Streetview and you have the ability to see what your destination looks like. http://goo.gl/n0cDFu
You can navigate just fine with Google Maps but the Driving shortcut makes it a little easier to get strait into that mode. For places you goto often.
You ask why do I need a GPS for places I goto often? Because Google maps gives up to date traffic reports. So you can quickly see how your trip to work is going to go for example.
c:geo is a Geocaching app. We'll save that for another post.
That brings us to GPS share. This app allows you to share your location with other people. Via all the methods you can share other information about yourself. For example you can text it to an individual. Making it possible for that person to find you in a crowd. Or you could share it on Facebook or Twitter to give a group of people a link to locate you.
You could also use it to mark a spot you want to remember. These are some of my favorite map apps. Do you have some to share?