Good Question. I been thinking that myself, what GPS people are using?
I've been using my iPhone with MotionX-GPS it's been pretty awesome. You can leave pins and photos along the way, and load and map sys you'd like, I run google. You can draw a path on Google Earth, export it as a KML, then convert it to a GPX file, then you can run it with MotionX on your phone.
Free online converter:
GPS Visualizer: Web interface to GPSBabel
Hope this helps, probably many options but this is the one I've used! :-)