i have a garmin gps III plus and am very happy with it. the data base it comes with is excellent, but i was wondering if any of you guys have bought, downloaded, and used the MapSource software for it. It seems like it would be great, esp. the topo ones. 100 bucks is a lot of loot to spend on something that may or may not be of any use. just wondering what the real world story is......thanks AIRBORNE!!