Nike Free 3.0
I got a pair of Nike Free 3.0s just over two weeks ago. Just wanted to plug the product, as they have instantly become the best pair of running shoes I've ever owned.
I wouldn't recommend jumping in right at the 3.0 if you haven't had any before. But I had some 5.0s and they now feel a little clunky by comparison. And you probably wouldn't want to try anything requiring sudden stops and starts or cuts. But for running they are great. I'm planning on getting some 7.0 trainers to replace my basketball shoes.
I guess the next step in the progression is to get some Vibram Five Fingers. Only one more step after that... barefoot.