Runners with GPS watches....

to_the_surface

I have a garmin 910xt, Had a polar unit before that got water in the pool and died a slow death. I use it because i ride a bike and i swim besides running and the little device keeps track of all my workouts. If i were only or mostly running it would be an absolute overkill.
If you run with music the motoact would serve both purposes (all the gps hrm speed/pace functions plus a music player all in one). If you carry your phone while running then the motoactv would be overkill as the music player in your phone would probably be better.
For simple i'd consider the garmin fr60. It doesn't have gps but it comes with HRM and a footpod which is a more accurate tool to measure running pace/speed and also will work indoors with threadmills. Basically you'd have all the info you need but it would not "map" your runs.
If you look up garmin factory outlet it runs like $120-130 for the fr60 bundle. It's also compatible with bike speed/cadence sensor in case you decide to incorporate bike riding in your routine.
I do not own one, and i do not work for garmin either, but if i wasn't swimming and just biking/running i'd have probably gone for the FR60. It is basically is a very inexpensive tool that would not break the bank when/if it needs replacement.
Good luck