As we all know, a single anecdote can suffice as proof of just about any point. Therefore I'll offer this up:
On Christmas (well known for the peace and goodwill bit) I had to dial 911 to report a knock-down-drag-out fight outside of a restaurant near my home. Some guy was beating the crap out of his wife, and the tactical situation was not one that I could have/should have intervened. Police response was 2 cruisers in under 30 seconds. And a third, 30 seconds after that.
This was in Manassas, Virginia, right along a major road, and I can't imagine they could possibly have been there faster. Therefore, if you're going to have to defend yourself, try to do it right next to a Denny's restaurant.
That said, I'll be fscked if I'll let a Bad Guy have even 30 seconds to get to me or my kids in my house...and I live in a 5-minute-plus response zone, absolute best case.
My home-security system is a Mossberg-Beretta active system.
[Edited because I should have proofread my proofreading]