Boxing is probably one of the single most effective martial arts I can think of for self defense or sport useage. If you think that elbows, knees, and kicks would give you the upperhand on a good boxer, you are highly mistaken.
Kicks, while quite powerful, are rarely good for the fight ending shot, elbows usually cause more cuts then KO's, and knees do more core damage that breaks people down over time. (It's much harder to knee people in the face then most people think.)
Your hands are the most likely weapon to use for fast effective knockouts, and boxing style punches will do the job.
I think it's very sad that this aspect of our western martial heritage is so incredibly underestimated. I'd happily pit good boxer against practically any other type of standup martial artist.
I thinkyou guys should watch this video to get an idea of the speed, precision, and power that a good boxer has
http://s45.yousendit.com/d.aspx?id=0H218OY82FX2K30OGUJY8DPDT0 Knee kicks. I get kicked in the knee on a daily basis, round kicks to the side of the knee (with the foot and the shin), I've been straight side kicked in the knee, had my knee stomped, never had any damage done to it.
When people try and kick me in the thigh I actually make it a point to try and catch it on my knee because usually it hurts them and they stop throwing that kick.
Grappling, if grappling is such a horrible idea in a real fight, then why do the manuals teach it? Why is it so successful in MMA?
Of course, another point is that it's usually not your choice whether or not you want to grapple. No matter how many times people assert that "grappling is a bad idea in a real fight" that doesnt make them any less likely to be taken down.
Grappling knowledge allows you to control the takedown insuring that you are the one that winds up with dominant position, from which you can control the fight on the ground, or you can get back up.
Also, it's pretty difficult to elbow people from the ground most times. Usually you lack the room and leverage to do so, but if you break someones arm, thats an instant fight ender.
On untrained grapplers I can usually get a takedown, dominant position, and a submission/break in about 15-30 seconds. You'd have a tough time matching that for a fight ender with strikes.