I did judo for a while too. I do not agree with Cimperiali that it teaches you to fall without much damage. It teaches you to do that on a mat, but when you have ever experieced falling on concrete, you would find that technique not so useful any more. Mats have damping, concrete doesn't. I wonder whether he really tried that once while skating. I have not a good experience with that.
Also, judo is not a real fighting sport, but just a sport with certain rules. OK, it can be used for fighting and self defense. But you may not have the luck of having an opponent whose vest or T-shirt you can firmly grab, your opponent will very likely not obey the rules in judo : punches are not allowed in judo, so you are not trained to react on them ( at least not up to a green belt, which I reached at the time). And you may also not have the space to do some more advanced techniques, like throws when there is a crowd around you.
Judo is actually a way of staying in condition as far as I'm concerned.
