I know there is a lot of interest amoung some regarding GPSs. I was curious as to how many people regularly use GIS applications. ESRI's ArcMap is the standard and I recently looked at Grass (for Mac) but didn't get very far wiith it. If you are at all interested in GPS applications, GIS greatly extends your capabilities. You can also use GIS files to make custom maps for Garmin GPSs.

I used MapInfo when I last worked for a mining company about seven years ago, and thought it was pretty good back then (on a pentium 133 ) but I haven't kept up with GIS since then.

GRASS, being open source, should be a good starting point for ambitious amateurs. A late friend of mine was a great fan of it. My personal experience boils down to a project with GE Smallworld that never really took off; I was supposed to help with some integration tasks, but funding evaporated.