I have a tried and test solution.
I hate the way keys jangle and make a noise when I run, so I only take the 2 keys I need to get in the house (have an extra set made if needs be if you have other keys on the bunch). I put an elastic band on the ring and wrap that around the keys, putting a twist at the end so that it can loop back over the end of the keys to secure them. Then pop them in my back pocket. They never cut through the pocket.
I used to have an issue with the elastic banded up keys knocking against my iPop Nano in the pocket until I worked out that I can put the band around the iPod a couple of times and put the keys under the band. Again, they don't jangle and don't wear through the pocket.
When the elastic band wears out, which it will, you're bound too find another red Postie band near your front door to use.