|The kid enjoying imaginary play with his Nerf gun.|
Still, I think toy guns, like the Nerf gun pictured above, are fine toys. I mainly feel this way because as a boy some of my favorite toys were guns. I had my Daniel Boone phase when my mock Kentucky long rifle was the coolest thing. Then I had a Star Trek pistol that flung many miniature disks as fast as I could pull the trigger.
The feeling that toy guns give rise to violent children doesn't resonate. I see my son having a good time and I'm reminded that toy gun play is more akin to playing dressup, assuming a role or pose and having a few props to bring the look forward.
Both my kids have a large array of images and objects in which to construct their identities. Allowing foam swords and toy guns lets them act out their favorite characters from film or book, which perhaps is a healthy way to deal with aggressive tendencies.
I realize I may just be rationalizing. But I suspect if the Nerf gun wasn't around other, less cool, objects would become de facto guns, such as sticks or a thumb and forefinger.