If you're running on the road, just prepare yourself for the creaky joints. Even the best shoes can't completely take the impact away, and six miles 3x a week will leave your knees in shambles within a few years. It comes with the territory.
I can't run at ALL on the road anymore without risking stress fractures. I've got no cartilage in my right ankle so I have to run on a padded track or in the grass. My knees are starting to go bad now, and my right hip. I really like riding my bike, but I just don't get the same intensity from it as I do when I run sprints or my 10 miles on wednesdays.
The doc I see for disability at the VA told me I have to stop running or i'm going to need a joint replacement by the time i'm 30. *Sigh*
If you figure out some magical method to running let me know too.