I switched from increasingly more expensive motion control shoes that I've been running in for at least 9 years to pure barefoot last summer. My shin splints that have bothered me for at least 5 of those years...gone. My arch pain...gone. I started from pure scratch, running about 1/4 mile a few times a week barefoot in between my normal shod 7-11 milers. As others have noted, there really isn't much in the street that you would think would be dangerous. If you're worried about stepping on something, it's very simple: look where you are going to put your feet.
Barefoot on a hard surface (concrete) teaches you very quickly how you should be striking, and I began incorporating better technique learned barefoot into my shod runs. Eventually got really sick of trying to run with a midfoot strike in "running" shoes with a thick heel, so I got a pair of FiveFingers; Haven't looked back, my $150 Brooks are now collecting dust in a closet. I ran a half shod two years ago in 1:51. Ran one last year in my Vibrams in 1:45, with half the training and a horrible pre-race day routine (read: imbibing to excess).
For the vocal doubters out there, it's rather simple. You can denounce barefooting all you want, but until you actually try it correctly, please stop, you aren't being taken seriously. It's fun, it's healthy, it will strengthen your muscles (trust me, I had no idea how weak my calves really were) and there is absolutely no reason not to try it; but slowly, patiently, and with a full understanding that you are learning to do something brand new that you likely haven't done since you were a child.
When I run barefoot, I smile a lot. Usually the whole run. Can you say the same?