What Bomba said.
It’s taken me an ankle injury that’s kept me out of running for the majority of 2010, and subsequently a great specialist physio who’s opened my eyes to the body’s capability, and the need for a thinner soled shoe to feel the ground as opposed to a over engineered running shoe that becomes a cast and lets your muscles degenerate.
I’ve switched to a certain type of cheap footwear – mimicing the Vibram 5 fingers but costing a tenth of, in order to simulate the barefoot running style but with some layer of protection for the sole, and am loving it.
The body knows how to run. Search YouTube for running style videos by Christopher McDougall (author of Born to Run). If you want to buy in to the expensive running shoe system that’s fine, but it won’t stop you from getting injuries.