I think the author of this article makes some good assessments...
http://www.gunsandammomag.com/tactical/location_090507/index.html
http://www.gunsandammomag.com/tactical/location_090507/index.html
I have long advocated what I call the SIG Principle, which stands for Simple Is Good. When considering where to locate a gun in your home, don't overthink it. Take into account your likely threat level (the example that I gave at the beginning of this article was extreme, but it was my reality at the time and I have never forgotten it) and place the gun accordingly. Keep them accessible but out of the hands of those who are not authorized to use them. While this sounds difficult, it really isn't if you just give it some unconventional, "out of the box" thought.