Ubuntu Linux ; the usual tools 'gpsd', 'gpxlogger', 'gpsbabel' do the thing very well. For mapping, I'm using JOSM (retrieving, building and using the svn version every time I use it), the appropriate photo plugin, and GPicSync for the "normal" photographs. While geocaching on foot or by bicycle, I try to make the battery duration longer by doing some tricks [www.lesswatts.org] and almost killing every unnecessary program running and shutting down all wireless devices (Wifi (unload the kernel module, turn it off via the BIOS (?) option by sending 0 to the wireless led 'dev' file ('acerhk' module), Bluetooth). Then, I stop gdm (killing X), open tty1, sudo gpsd..., open tty2 gpxlogger, and go! Sometimes, for fun, I do some wardriving/warcycling/warcycling, and instead of gpxlogger I use kismet that give me logs in several formats, ready to be used. Afterwards I create a Google Earth KML from the Kismet XML to see the networks, and export the GPX (what a great and simple format!) to my "big monitor computer" ;-)