I think the argument that my save the everything friends would make is that if fewer people had guns, there would be a similar amount of violence, but a lot fewer deaths. More stabbings, beatings, etc, but people would live. Personally, I think that covers some crimes of passions, but I wouldn't underestimate American ingenuity in murder. The news would be more interesting, at least, what with women poisoning their cheating husbands and teenagers driving their mom's tahoe onto the football field and mowing down half the team.
That's all fantasy, really though. People for whom crime was a business would still have guns, and in my experience (all now well beyond any applicable statutes of limitation, of course :p) it's not that hard to get things that are illegal if you really want them and have the cash.
Having said all that, and agreeing with our founding fathers that guns are sa-weet shit, I'm not so sure any random joe should be able to buy AK-47s at the flea market.
Also, while I didn't read the article this conversation springs from, imho the primary philosophy of the 2nd am (defense of the people against tyranny) becomes pretty much moot when tyranny has f-14s and abrahms tanks and supersoldiers that dont sleep and can breath underwater and don't frickin die. I may have seen one of those on the x-files. That doesn't necessarily mean it isn't true.