Free USGS Topo Maps...

You can now download free electronic versions of the standard USGS topographical maps, the ones that are familiar to any serious hiker, four-wheeler, hunter, etc.  In many ways these electronic versions are superior to the paper version: you can magnify them to any level (they're vector-based, not rasterized), and they have layers that can be switched on and off.  Furthermore, the few that I've tried include photographic coverage (also in a switchable layer) – not satellite photos, but aerial photos of quite high resolution.  Nice!