My 2 bits:
We didn’t have our boys cut.
When asking my father (a pediatrician and neurologist) about it, he stated that he was unaware of medical benefits, that there are known risks, and that he and my mother had decided out of aesthetic concerns (which is pretty common).

I personally don’t think the aesthetics are that important. If I had been aware of any benefits I might have thought differently.
I am aware of non-conclusive evidence of medical benefits now.
http://pediatrics.aappublications.org/content/early/2012/08/22/peds.2012-1989
Again, non-conclusive and I am not sure about what decisions I would have made with this evidence in hand.