You ever read Born to Run? I would recommend it to anyone who runs and its a fascinating story for anyone who doesn't run.
I am not a huge believer in shoes anymore. I used to stick primarily to the Asics Gel Nimbus which went about $120 a pop. I replaced them about once a year. After reading Born to Run I decided to let them go a little longer and see if my performance declined or my body hurt more. Nothing happened so I started to buy the cheaper, less cushioned shoes, still around $80/shoe but they are much lighter than what I used to run in.