Well, I carry The 92 FS, stainless long before the law-enforcement professionals and military were carrying it, and now as a backup I carry a Carbon 15 pistol in .223, much to most peoples surprise I've been in some pretty hairy shootouts and all the professionals seem to say shootouts last fewer than a few seconds, I beg to differ since my last hot encounter lasted more than a half hour, I think they ran out of ammo, and I lost a 97 GMC Jimmy as it was too covered with holes to drive afterwards.
Since then I cannot be too prepared I have bought a Level 3a vest I don't wear unless I'm going to a troubled area of town, but it is kinda small and a littlie to warm this time of year, so I just upgraded my backup firepower to a small Carbon 15 with a 100rnd drum mag, a completely last resort piece of hardware. But my primary carry gun of choice is the full size Beretta 9mm 92 FS with a 15 rnd mag and Glaser blue fragmenting ammo. No holster just tuck it in my belt pull over my shirt and off I go.