I know there has been some talk on this on here recently, in addition to an article in BB magazine, a few months ago. I'd like to look at a few different areas of this. Of course, this is just to get the ball rolling. Hopefully we can expand into other areas, from there. 
1) In that BB magazine article, the author was talking about doing a shot to the eyes. This was done obviously with the hands already up, in a non-offensive posture. The idea that I got from the article, was that if your opponent can't see, he can't fight, to disable him enough to get away. Someone wrote in to the editor, commenting on that article, concerned over the use of the hit to the eyes, vs. something less likely to cause possible permanent damage.
2) Some people are concerned over the use of any pre-emptive strike. They're most likely viewing it as, if someone sees you throw the first punch, you will most likely be seen as the aggressor, instead of the other guy.
My thoughts: Personally, I'm a big fan of the pre-emp. IMO, the other guy doesnt have to throw the first strike, to be considered the aggressor. His actions are enough of a sign. Problem is, to the lay person, its the physical action of actually throwing the strike, vs. his body language. I disagree. Frankly, if someone wants to yell, scream and swear at me, they can do that from a distance. They dont need to be in my face to get their point across.
So, their action of moving in on me, despite my repeated verbal commands, ie: back off, I dont want any problems, my hands up in a non-threatening manner, is enough for me to take their actions as aggressive.
I'm sorry, but I'm not going to wait until this guy is standing 1 in. away from my face, loading up his hand, and the punch 1in away from my face, before I do something.
As for what pre-emp to use...wow...the list is pretty big, IMO. While I do see the point the author in the BB article was trying to make, I dont feel that we have to take the guys eyes right off the bat. I view the pre-empt as an opening....something to buy me time to follow up with other things. Something to take his mind, momentarily off of hitting me, and change his thinking to, "Oh ****, what just happened??"
So, for example...from the hands up position, a palm to the face. Hopefully, this will buy you time to a) get the hell out of there or b) follow up with other strikes.

1) In that BB magazine article, the author was talking about doing a shot to the eyes. This was done obviously with the hands already up, in a non-offensive posture. The idea that I got from the article, was that if your opponent can't see, he can't fight, to disable him enough to get away. Someone wrote in to the editor, commenting on that article, concerned over the use of the hit to the eyes, vs. something less likely to cause possible permanent damage.
2) Some people are concerned over the use of any pre-emptive strike. They're most likely viewing it as, if someone sees you throw the first punch, you will most likely be seen as the aggressor, instead of the other guy.
My thoughts: Personally, I'm a big fan of the pre-emp. IMO, the other guy doesnt have to throw the first strike, to be considered the aggressor. His actions are enough of a sign. Problem is, to the lay person, its the physical action of actually throwing the strike, vs. his body language. I disagree. Frankly, if someone wants to yell, scream and swear at me, they can do that from a distance. They dont need to be in my face to get their point across.

I'm sorry, but I'm not going to wait until this guy is standing 1 in. away from my face, loading up his hand, and the punch 1in away from my face, before I do something.
As for what pre-emp to use...wow...the list is pretty big, IMO. While I do see the point the author in the BB article was trying to make, I dont feel that we have to take the guys eyes right off the bat. I view the pre-empt as an opening....something to buy me time to follow up with other things. Something to take his mind, momentarily off of hitting me, and change his thinking to, "Oh ****, what just happened??"
So, for example...from the hands up position, a palm to the face. Hopefully, this will buy you time to a) get the hell out of there or b) follow up with other strikes.