Well, I don't like to miss an opportunity to advance my cause;
For knives, I practice the Spanish style, variously known by the self-referencial names of el cuchillo or la navaja, or under the general headings of destreza or El Nobilisimo Arte De La Esgrima.(Spanish word from a German root, "skirmjan", meaning "to brandish", if you were wondering) Also reffered to as tirar a la navaja, when using a navaja that is. Much as they play at a sport, they strike or fence at a weapon. Psychologicaly curious. Good art anyway.
Sevillian Steel sucks and in no way accurately reflects this art at all, if you are interested and read Spanish, I reccomend going right to the source, Manual Del Baratero, O Arte De Manejar La Navaja, El Cuchillo, Y La Tijeras De Los Gitanos. by Marion de Rementaria, published in Madrid in 1849.
For unarmed, I do boxing. Not the modern, watered down and rendered safe by lame rules and gloves sporting version that still manages to give good account of itself, I practice the older, traditional combative styles. There's a world of difference.
No illegal strikes or moves, or rules of any sort really, and just about everything everybody thinks boxers don't do is actualy used, for instance elbow strikes, eye gouging, throat crushing, low line kicks, stomping, jumping up and down on fallen opponents, and so forth; though the offensive base is still the punch, only it's a penetrative vertical punch struck bareknuckled at specificaly vulnerable points, backed up by good grappling skills.
It works quite well. It's made short work out of Billy Badass more times than I can count, and it's humbled Asian stylists who thought they were unchalenged in the area of unarmed combat.
If I had to reccomend only one source on the combative style of boxing, it would be Edmund Price's Science of Self Defence, published in 1867 in New York. Awesome book, excelent info and an irreverent sense of humor. A favorite quote, regarding close quarters fighting, called fibbing;
"After securing his head in this position you may pound away upon it very pleasantly, with the other occasionaly changing.
It will be altogether needless to say that we are reffering more particularly to your pleasure, than that which your opponent may enjoy during the operation; as singularly enough this affectionate fashion of bestowing your favors, seems scarcely so agreeable to the recipient as it may be to yourself. In spite of his dislike, this may however be persisted in, either in the Prize Ring, or in a personal "scrimmage," whenever you have an opportunity for paying him such a delicate attention. If handsomely done, it will by no means improve his beauty, as it is tolerably certain to impair his temper."
The English stuff is good too, but tends to be more sober and technical. Price has a great sense of humor. Huh, Colonials...
But I'm getting off topic I suppose. How does this carry over into survival, besides obvious benefits of improving agility and physical fitness?
Well, one of the first things a boxer learns is to keep his cool and never strike a blow until he has thought of it's follow-up. What better survival philosophy could there be?