I suppose that title probably dates me a bit. Oh well.
A lot is made these days of studying martial arts for self defense and I'm inclined to think of this as a good thing. However, there is a great deal myth, balderdash, and outright untruths associated with them and learning effective fighting techniques from a martial art is rarely as straightforward as it should be.
I shall endeavor to dispel some of these myths first:
1. Martial arts are useless in a fight. I list this one first because, like many myths, there's a kernel of truth to it in many cases. In fact, this one would be a truism if it weren't applied with such a broad brush. However, the right system with the right instructor can be a devastatingly effective means of defense. More on that later.
2. Martial arts are just for kids. This, of course, comes from the fact that children and teens are much more likely to be interested in them than adults. Kids are naturally more energetic and rough-and-tumble than adults, but that's hardly an effective condemnation. If you want to learn to protect yourself, you're going to have to work at it and be willing to take some knocks.
3. If I have a gun (knife, baton, OC spray), I don't need to know how to fight with my hands. Sheer and utter balderdash. I've been carrying firearms and other weapons the entirety of my adult life and I've had many occasions to defend myself with my hands. I've had to break a hold, kick my attacker in the knee, and then back up to draw my sidearm, just to give one example. Just talking to some of the people I've worked with, I could come up with two dozen other example at a minimum.
4. This particular style is the only effective one, or that particular one is totally useless. While I've been guilty of thinking that way at times, the fact is the effectiveness depends largely on the instructor, and how much he emphasizes defense, and the student, and how much he takes from it. While certain martial arts are certainly less likely to be useful than others, they all have something to offer.
5. I'm a small person and could never fight off an attacker, or I'm big and don't need any training to defend myself. Again, a kernel of truth. (Another myth is that size doesn't matter, but I'll cover that here.) There's an old joke among martial artists, 'Size doesn't matter, unless the other guy is bigger.' In other words, just because your opponent is smaller, doesn't mean he can't beat you, or if you're smaller, well, you may be in trouble. Size does matter, but it doesn't necessarily trump all other factor. With two people of equal skill, speed, and fitness, yeah, the bigger one will probably win, but how often does such a match up happen? In the extreme, can a tiny little girl beat a huge, muscular man? Yep, I've seen it both in the dojo (where I was the big muscular guy) and in the real world (where I saw a female cop throat punch a suspect armed with a knife and follow it up with a shot to the wedding tackle). Above all else, the will to win/live is the most important thing.
To my way of thinking, there are two basic schools of martial arts. Man-handling and skull-cracking (apologies to SJ games).
Man-handling is largely about subduing your opponent with a minimum of injury to your attacker. It's primarily useful for police, prison guards, and others who may want to subdue a subject with minimal injury. To my way of thinking, this makes it inappropriate for self defense, despite the popularity of 'soft' martial arts for just that purpose.
Skull-cracking is about taking a perfectly healthy human being and reducing him to a quivering mass of shattered bones and burst internal organs. That alone highly recommends for defensive usage. Soldiers, defensively minded citizens, street fighters and many others primarily will use skull-cracking.
The distinction is a bit blurry as most martial arts will include elements of both, but if you look critically, you can usually distinguish a particular move or series of moves as one or the other. It is not striking vs. grappling, it is the results they deal with. While pretty much every strike is a form of skull-cracking, I've seen, and used, a lot of grappling techniques that pull joints out of socket or out right break them.
If you have to defend yourselves with your hands, obviously you want use whatever will give you the best chance to emerge intact. This is why I strongly discourage people to grapple with their attacker. Most people, when grappling, will do just that, grapple. An experience street fighter may tackle you and try to take you down, but he's also going to try bashing your head into the ground, head butting, punching, kicking, or whatever else he can to hurt you. Without experience, it's very hard to grapple effectively against someone who doesn't follow sparring rules. If you can fight on the ground like that, hey, go for it. Otherwise, you're best bet is to break contact, get enough distance to safely draw a weapon, and do so. Breaking contact and getting distance will almost certainly mean getting your hands dirty as your attacker is unlikely to want to let you move away. Hence the skull cracking. Hurt him and then you can move away unhindered.
All that having been said, if you want to learn to defend yourself, you have to find someone who will teach you how to fight. Maybe they won't share my exact views on how to best defend yourself, but they should at least have the same mentality. The problem is, with the commercialization of the martial arts, especially Asian arts, there has been a drive to make them more 'kid-friendly' and kinder/gentler. While any training is probably better than none, you should try to avoid these instructor like the plague. You want an instructor who believes in teaching fighting, not sparring. They can be very hard to find, but they are out there.
How do you tell a good instructor? Well, you want someone who encourages full contact sparring, does his best to minimize injuries, but understands you need to learn how to take a hit and keep going. Minimal or no emphasis on forms or katas (I know I'll get flamed for that, but so what, I'm fair sure I know what I'm talking about). A really good sign is an instructor who occasionally will bring in a red man suit and allow the students to practice the really damaging techniques. An emphasis on the proper execution of move is not, however, a bad sign. Power comes from leverage and technique, so it's a good sign if he wants you to do it a certain way. Lastly, an instructor should know that real fights never occur in a semi-scripted manner, ie strike, counter/block, back off, strike, counter/block, lather rinse repeat. It looks pretty and allows people to show off their more complex moves, but very poorly simulates a real fight.
Where are you most likely to find these instructors? Well, I can tell you generalities, but the fact is you just have to go see for yourself. Tae kwon do is, in my mind, one of the most commercialized, nerfed martial arts in the US and your odds of learning effective defense from it are tiny. However, when I was taking it as a kid, I did meet a few instructors how taught how to fight and fight to win. Not my own instructor, although he wanted to, because he was part of a multi-national school that wanted to encourage kids to join up. On the flip side, of the many Jujitsu instructors I've met, I'd say slightly more than half of them were the right kind of instructor and while I have yet to take Krav maga (it's on the list), I've never even heard of an instructor for it who doesn't teach how to defend yourself very effectively.
In the end, however, you just have to find the right instructor.
Edited to add:
It occurred to me, a bit late, that the above post makes it seem like I disdain any martial art's school that doesn't teach effective self-defense. I didn't mean to. The above was written from the perspective of learning effective self-defense from martial arts. There is nothing wrong at all with going to a dojo, with your kids even, for fun, competition, getting in shape, being part of a tradition, or for any other reason.
Also, the 'softer' methods I refer to as man-handling are perfectly appropriate for use in self defense against someone who you don't want to hurt and can subdue gently without placing yourself in undue risk. Again, I was speaking in the context of life threatening danger.