Okay, let's play some catch-up.
I think it goes without saying that the number of dead in Mumbai was a function of how many of the local civilian population was armed and able to respond to the attack, whatever each civilian may have seen of the attacks.
In my view, attacks like Mumbai are not just possible here in the US, they are likely if not inevitable.
There are not that many courses of action when the bullets start flying. I've tried to cover them all at several posts here in the past. But perhaps I've forgotten one: to carry or not to carry.
Some governments make the decision for you. Some make mix of it. For example, Washington State permits both concealed and open carry. Seattle PD has a tolerance for OC as long as the person going OC is behaving himself. But the Mayor of Seattle is trying to ban all handguns in the city; whether concealed, carried openly, or sitting on a nightstand. Still, we make our own decisions and live with the consequences, intended and un.
What's the first question you need to answer when considering purchase of a defense firearm?
What will I do with it if my life is threatened?
If your answer is not I'll use it properly to defend my life and those around me, then don't bother buying one. Forget about it.
If you're going to use it, then your next choice is which pistol. The question you need to answer in making that choice is How much will I train with this?
If you're going to spend a few bucks on range fees and a box of bullets once a year, and keep the gun under your pillow the remaining 364 days, you should probably get a 5- or 6-shot revolver. A .38 caliber is probably going to do the trick for those who make this choice.
If you intend to get a concealed pistol permit and carry all the time, you should get a semi-automatic pistol with at least two spare magazines. Unless you're going to train all the time, like once or twice a week, I'd suggest a 9mm DAO pistol. If you put the right ammo in a 9, and learn to shoot it, it's just as effective as the larger, louder calibers.
I carry a Browning HiPower 9mm ~ no gun for a novice. Here are some recommendations from Walt Rauch in the 2009 Guns Annual. These recommendations are all inexpensive handguns suitable for self-defense.
The Rossi Model R35102 .38 SPL +P 5-shot revolver. +P means it can handle .38 cartridges with a smidge more powder/power in them. The ammo boxes are labeled as such.
The Kel-Tec PF-9. Never fired it but I know cops like 'em as back-up guns.
The Smith & Wesson Sigma 9mm. I've carried and shot this pistol for 7 years as a duty weapon. I never had a problem with it, qualified "Expert" every time. I think it's a good gun.
For those seeking another or bigger bang, with economy still on your mind, I suggest:
The Maverick 88 Slug. It's made by Mossberg ~ you can't go wrong with this baby. Only shoot slugs through this one. If you absolutely must have a "street-sweeper", get the Maverick 88 8-shot Security.
If you prefer on-line shopping to comparison shopping at the gunshops in your town, you might try Impact Guns. If you're going to buy a pistol, go to the nearest shooting range and try out several in the caliber and price range you prefer. Then try to find the best price, in-store or on-line, it's up to you.
Remember, it's all about training. I can offer some here for free but you need to get some hands-on training with whatever weapon you choose.