Good advice. In particular, it's too easy to view the gun's style. Do NOT consider that it looks cool, tough, etc. The fact that the .50 Desert Eagle looks menacing is not going to save you from the fact that you (or me, at least) just can't properly shoot a gun that's so big and powerful. Being able to use it properly is much more important.

Also, don't just assume that it's going to be an auto like a Glock, etc. IMHO a simple dual-action [1] revolver is probably a better choice for defensive situations, precisely because it is so simple. A revolver will never let you down: you can always just pull the trigger again to get to the next chamber. By contrast, autos are prone to jamming, not to mention a misfired bullet; either way, you're now at the mercy of the bad guy. Your primary concern in this area is dependability.

[1] "Dual action" means that you may cock it for better trigger pull, but if you don't, you can still fire it with just the trigger