MSD, I know you are a contrarian, so consider reading some of the anti-high-tech footwear stuff that's out there. I won't say anymore than that, because I'll be starting a holy war.
I second eck - go to a place that specializes in running shoes. The running store in gainesville, va is fantastic. They videotape you running on their treadmill to identify how you step, then get shoes to provide the right level of support. It takes a while, but I love the shoes they gave me and it only costs about ten bucks more than Dicks.