I see guns more as a deterrent than an actual defense measure. A criminal will be more likely to assault someone on the street if he knows there's little chance that person on the street is going to be packing (even if the criminal himself doesn't have a gun). So there's less deadly risk in going out and assaulting people.
I honestly believe that average people should have the right to weild deadly force (now just how deadly is a point of contention though). Because bigger, stronger people already have that ability, even unarmed. Sometimes when someone is being violated in an extreme situation, there's really no possible recourse other than to whip out a gun and threaten them with it. To say just leave it to the police puts it in the hands of a beauracracy which often can't get anything done.