Do you send your child to a coed school or a boys/girls-only school? Why?

I don't think co-ed schools begin to show any inherent benefits or detriments until around adolescence. However, when my daughter reaches the appropriate age, I'm going to play it by ear but will lean towards co-ed. I went to co-ed, and my older friends seem to think sending boys and girls to school together lets them assimilate in an easier fashion, and though it seems counterintuitive, lets them get all of the fuss of seeing boys/girls out of their system.