option to save/load all preferences to/from a file
I worry a little bit about a preferences import/export. Some preferences could be machine specific (like an import/export directory) that might be different (or not present) on another machine. That could cause all sorts of issues. Also, this would reset the GPS settings - which could be a pain if one user has a GPSMap 60, and the other has a GPSMap 62 (or another combination of incompatible units.)
These are not insurmountable, but makes adding this feature not as trivial as it may seem.