I'm in the US Infantry and we spend a fair amount of time every week on hand to hand combatives. Although I enjoy watching and participating in boxing the truth is most fights end up in a grappling match on the ground. Learn how to punch, but if you really want to be able to fight and overcome size and strength differences get into Judo/akido or brazilian jujitsu..I'm 5'10 and 215 pounds and my platoon sargent regularly can make me cry like a little girl when we wrestle...and he only weighs 170. Brazilian Jujitsu combined with some good punching skills is the best way to go for self defense.