For home protection and making sure you hit the target get a shotgun. A tactical Mossberg 500 12g would do the trick.
Something like this:
http://www.impactguns.com/mossberg-5...813524407.aspx
Unless you're a really good shot and have a lot of training, odds are a handgun isn't going to do you much good unless you're at close range and you still run the risk of not putting them down.