I just finished reading the book "Born to Run" by Christopher McDougall, and I must say that it's one of the most inspiring books I've read in a long time. It's a tale about the Tarahumara indians, great ultra marathoners and self improvement. It also supports the claim that most of the ailments we normally associate with running actually can be blamed on the cushioned running shoes that taught us to run incorrectly.

Personally I've stopped using cushioned shoes at all when I run. If the road/path is good enough and the temperature is high enough I prefer running completely barefoot. If not I run in my Vibram FiveFingers Bikilas or my New Balance Minimus Road Zeros.

Take a look at the video below (McDougall on humans being born to run) and pick up a copy of Born to Run (or get it on your Kindle). If you would like to try barefoot or minimalist running yourself, I recommend that you check out Barefoot Ken Bob's book Barefoot Running Step by Step to make sure you learn the right technique off the bat. If not you risk a lot of other injuries, and that kind of defeats the point.