Alright i've decided I'm going to get a Glock handgun sometime in the future. The reason I want it is in case I ever need it for an emergency or need to defend my home. I have heard Glocks are very reliable handguns and are easy to use. One thing I noticed is that they have alot of different round choices for them. What would you suggest I get? 9mm? 10mm? .40cal? Any opinions would be helpful.