I'd say it really depends on what your application is. I really like Terrain Navigator Pro (TNP), but I definitely wouldn't say is has anything other than very limited drawing capabilities, I would call it "annotation capabilities." It will calculate distances and areas though, although the accuracy is limited by the fixed map scales. I'd round it off at about 10 linear feet and maybe 100 sqaure feet.
TNP is a USGS mapping software that you typically purchase for an entire state. Each state typically costs about $300, but what's nice is that you can import GPS points (or points from any coordinate system for that matter), or create points for any coordinate system and transfer to the gps device. It provides ballpark digital elevation data for wherever you have the mouse located, and what I find to be the most useful feature is that you can export the USGS maps (or sections of the maps as defined by the user) as georeferenced tiff files that can be imported directly into your Cad program so that it "falls" right into place.
Again, it may not be the best for your particular application. When I want to do what it sounds like you're wanting to do, I'll convert the GPS points to state plane coordinates (since I usually work in state plane coordinates) using Corpscon batch convert, then import the points (after conversion to state plane) into my CAD program, which obviously has "unlimited" drawing capabities.
