I’ve owned everything–and I mean everything–under the sun at one time or another, and if you came to me as a friend to borrow a gun, and taking your situation into account, I’d definitely loan you a 357 magnum revolver.
If you go to work actually thinking you may not come home, then the ability to defend yourself is top priority. To hell with looks. With this in consideration you need stopping power greater than a 9mm.
Glocks, Beretta, Smith & Wesson, and all other automatics are fantastically designed and todays handguns are stress tested to death, but automatics all have one thing in common: If you pull the trigger and hear a “click” (misfire), or if your first shot doesn’t drop your opponent and the hull jams on you, you’re going to need time to recycle the upper to bring up the next round. With a revolver, you simply pull the trigger again to get to the next round, and jamming isn’t an issue.
My Glock was ugly as hell (the top of the thing looked like an aircraft carrier deck) and looked like it was carved from ebony, but I must admit that the smooth, plain surfaces made carrying it one of the best experiences I ever had with a handgun. You can get to it rabbit-fast and it felt good on you, which is the reason I carried it more than any other firearm. Also, A Glock is arguably the toughest son of a bitch of a gun ever designed and you can abuse the hell out of one and it will fire every time. They are highly reliable, but if you get one, I’d recommend a .40 or better.
Beretta, especially the 92 and 96 models are beautiful and also proven firearms that can take a beating. For me, it’s a toss up between these models and the Glocks for reliability, but the Beretta certainly is better looking. The edge goes to the Glock for comfort when carrying.
I own a Smith/Walther SW99 that I love because it bridges the gap between the Beretta and the Glock nicely, and at .40, it will make short enough work of your attacker.
Again, I think you need a .357 Magnum Revolver. Admittedly misfires are a rare thing these days with round technology, but if I had to face the possibility of violence every single day, I’d want to know that when I pulled the trigger, the son of a bitch is going to fire. Or, I can just pull it again.