No surprise there are other map geeks here.
I used to highlight my travels and make notes on paper maps, but eventually they wear out and I would throw them away without transfering the information.
Now I have a Delorme handheld GPS and Delorme TopoUSA (they came as a bundle). I opted for the travel kit which allows me to power it from the cigar lighter plug and just leave it on my dash for a clear view of the sky. The battery is only good for a few hours, so I when I'm hiking I usually only power it up to get a fix and save a waypoint. The screen is pretty small, but at least it's in color. It has a Gigabyte of built in memory and will accept SD cards upto a gigabyte. I can load the handheld with topographic maps down to 20 foot contour intervals for a very large area (easily twice the size of Santa Barbara County, CA.)
I usually make a track of where I go (at least once I leave pavement), take waypoints of the interesting things - campsites, springs, photograph locations, etc. - then transfer the information to TopoUSA. I like that you can convert the waypoints to a hyperlink. If I have any pictures associated with a waypoint, I make the hyperlink go to those pictures. It's interesting to sometimes playback the tracks to see how fast (more often how slow) I was going, how often I stopped, etc.
I also have a few friends with TopoUSA, so we can easily share waypoints, routes and tracks via e-mail.