MotionBased.com is a very cool site that allows you to upload GPS track files, and display them superimposed on street maps, topo maps, and overhead imagery. It also allows you view speed and elevation profiles from your track files. Unfortunately my GPS unit does not store altitude data with its track files, so I can't generate elevation profiles.
The only downside is the images are generated as Adobe .svg files. This gives them a lot of cool features, but not a lot of software can read the .svg format.
I take screen shots of the images I like and save them as .png or .jpg files which are much easier to read.