I like to know where I have ridden and how I'm doing, and like to follow others, so it's Strava for me. The flyby viewer is really neat. Then there's VeloViewer for awesome stats and graphs.

I rarely map out rides beforehand and do NOT like attempting to follow a map or a cue sheet during a ride (will use the navigation system in my car when I HAVE to be somewhere or if the route is particularly complicated, but otherwise I dislike it), so MMR hasn't piqued my interest.