I've also chatted/posted/whatever to a EMT (He might have been a full Paramedic) who had previously decided to carry a knife with him on the back of his belt for cutting through seatbelts until he had his back to a crazy drunk in a hospital ER and realized how dangerous the situation could have become. I pointed him towards a Safety Knife/Car Emergency Tool that doesn't appear to be on the market any longer (I'll look more later.).
Can't sleep so I found my original source for the safety knife in question and looked up the company that made it. Appears it's not on the market any longer. Pity.
The one I got for my father is apparently called "
Res-Q-Me" now (I think it had a different name back when I got it.). ThinkGeek has an updated model for sale called the "
"BodyGard 5-in-1 Emergency Tool". Too many bells and whistles on that one for my liking, but the additions would be good for someone civilian in an urban environment. ... Which describes me, actually.
I know I put a lot of thought into the equipment and modifications thereof for my characters. But I'm a weapon and vehicle nut that likes to think I'm a writer, so that might have something to do with it.
Whereas I'm pretty much the exact opposite. My characters carry a handful of pretty simple weapon loadouts, based on their personality. Ruger Warhawk, Ares Predator, or Salavette Guardian with either Ex-Ex or APDS rounds. All Smartlinked with custom grip, and that's about it. If they edge more twoard the pacifism scale, an Ares Squirt with Gamma Scope. For heavier weapons, almost always an Ares Alpha. And for really heavy weapons, Vindicator Minigun and/or Panther Assault Cannon.
My one exception is Rush, my Missions character. But he was a bit of a twink with two-gun fu and a pair of Lonestar Ruger Thunderbolts tricked out to give him every bit of recoil comp he could beg, borrow, or steal 
I'm not deriding the idea of simple loadouts. Especially if you get a group that handles things the same way, it allows for crossloading and exchange of equipment in combat without extra need for training or additional extras (Such as different magazines or ammunition for different weapons.). There's a reason NATO and the Warsaw Pact standardized a number of concepts for military firearms.
For myself, thinking of the background of a character, a vehicle and/or weapon is a personal choice made from a variety of options down the line. If they upgrade to a different firearm, it's likely due to extensive testing and getting a better "Feel" of the weapon, as well as other options. I also typically pick cool looking weapons, particularly intimidating designs (I loved the Ares Predator I for that, BTW.).
I could go into greater detail, but I've already had one group of people tell me to shut the hell up.

Unless someone here is willing to take the flak and get me going...