This is a very heated question here in the states and is an issue that the politicians exploit with zeal when an event like that at Tech occurs. I have a niece who is a junior at Tech and thankfully, she was unharmed, however, I do have friends who were directly affected by the shootings. Blacksburg, VA is only about 2 hours down the road from us here.
In our Constitution, we have the second amendment:
"A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed."
IMO, it's clear and if you read the framers' thoughts and reasoning on the subject, it is very clear what they had in mind as well. That said, there are many who interpret this amendment differently and would like go even further in restricting gun ownership by the general populace.
Where I live, here in rural north western VA, in the Shenandoah Valley, I don't know anyone around who doesn't have a gun of some kind. It is a socially and economically diverse region with long-time residents and recent transplants from all over the US, a few from Europe. In addition, there is a large Sportsman community of hunters and animal lovers and we have a healthy wildlife population.
We've lived here for almost 10 years and the only crime that I know of in our general area is a stolen chainsaw a few years back. Many folks leave their doors unlocked, some homes don't even have locks and keys can always be found in cars. I've seen police presence out there maybe three times in that whole time.
People around here "know their place". What I mean by that is, people understand and respect each other and they respect (for the most part) the "place" we all live and have chosen to make our homes. And likewise, if you are a member of this community, there is an expectation that the understanding and respect will be reciprocated, no matter who you are. There is an ethos amongst folks and perhaps this is why we have a peaceful, crime-free community.
IMO, the "gun thing" is just one small part of it to be understood in context when discussing the community as a whole. Now, that said, I do believe that "city-folk" or "outsiders" who might have ill intent, who might be considering coming to our community to do wrong, give it a second thought we they realize that just about everybody out here is armed in some form or another. So yes, I believe it is a deterrent to a certain degree.