I lovelovelove my Browning HiPower, but if somebody said “You can only have one firearm” (hypothetically, of course) it would be either the M1991A1 or the Kimber full-size Custom Classic I own, both built by Alex Hamilton and dead reliable. I use them only for shooting matches because the idea of them in an evidence vault after a justifiable shooting unnerves me.
Always intended to argue that since there was no issue as to who fired the justified shot, that the only thing relevant to the bullet that went through the bad guy would be the (easily replaced) barrel of my handgun. I would further argue that now, more than ever, I needed a firearm for personal protection. That is all I would offer them, and hopefuly my attorney for the occasion would convince them.