I do spatial analysis for a living using ArcGIS, I also guest lecture at Cornell on the same stuff. The best mapping software is ArcGIS but it costs $2500 and each extension is $1500 and you need at least one extension to view raster based data. Most counties have there own spatial data that goes past the orthographic images that are on google earth. You can get elevation, landcover, species richness, lakes, streams, soil, tax parcels, ect... With this software I can give it a list of things to look for and to rank them, for example I can say show me all areas that are mostly oak, that are on a elevation over 20 degree and are at least 1/4 mile from water. The analysis I am currently doing involves looking for 24 variables. I help land trusts create conservation plans. I have two state lands near me that are very large and I do a simple check of landcover and elevation before I go to hang tree stands. In late summer when I pick mushrooms (chantrells and black trumpets) I do a search for hemlocks and soil type. The options are endless and there are tons of web pages out there that have lots of free data. There is probably free software out there that will allow you to view shapefiles but you need to fully understand how to project the data for it to work.