I think you'd reduce certain crimes. However, there's two things to keep in mind:@ General Zod: Yes, obviously, people who desperately want to own a gun will get one if they try hard enough, even if owning guns was illegal, but do you think the average Mr. Smith-type of guy would risk making himself a criminal in order to get a weapon for his own protection? I doubt it.
1. The overwhelming majority of gun crimes are committed with illegal guns. This would seem to indicate, that by making guns illegal, the only people who would be left with guns are the criminals.
2. Gun ownership lowers crime. Evidence shows, that when states allow conceal carry, crime goes down across the board. A criminal is simply less likely to rob or rape you if he thinks you may have a gun.
I think it's important to recognize that we live in a violent culture. Probably because we're sexually repressed as a nation. I'm not sure that could be legislated away, even if there was support to do so. I think if you took guns away from law abiding citizens, home burglarly (for instance) would sky rocket.
Zod