In light of the soon-to-be James Toney fiasco...

Who would win...

Boxer vs MMA fighter? How many times in the last ten years have you heard that question?
Boxer vs Karate? How many times in the last 25 years has that been asked?
Boxer vs Wrestler? How many times in the last 50 years has someone asked that?
Acceptable answers to how many times have you heard those questions are as follow...
A Bunch. Too many. What's wrong with people?

Basketball player vs Volleyball player? How many times has that question been asked?
Baseball player vs Tennis player? How many times have you heard that question?
Huddler vs High jumper? How many times has someone asked that question?
Acceptable answers to how many times have you heard those questions, are as follows...
Never. What's wrong with people?

The definitive answer to who would win between a boxer and any of the above is...
A Boxer at Boxing.
A MMA fighter at MMA.
A Blackbelt at Karate.
A Wrestler at Wrestling.

And...
A basketball player at basketball.
A volleyball player at volleyball.
A Baseball player at baseball.
A Tennis player at tennis...ect...

Do you get it? They are all ridiculous questions. Any athlete at or near the top of their sport would destroy any athlete near or at the top of their sport, in their own game. Any MMA fan that says a George St. Pierre could compete with Arthur Abraham or Bernard or Kelly is quite dense (and is asking themselves what quiet dense is) or is ajenda driven.

And anyone who says Arthur Abraham or Bernard or Kelly wouldn't get smothered and tapped by a GSP is either an imbecile (and needs to google imbecile to see if it is a good or bad thing) or ajenda driven.

Any quality boxer's main defense is the ablilty to slip a punch. If you make it a habit to slip every jab or duck every hook, it will get you kicked in the head in MMA.

In the cage even the best strikers often throw punches walking foward instead of shuffling. You will get knocked down ten out of ten times if you do that in a ring. My main point is, when the rules change, so does the training and technique. As it does in basketball or volleyball or baseball or tennis. The question itself is invalid.

A more legitimate and interesting question would be...
Could the best MMA fighter in the world beat the #100 boxer at boxing in his weight class. Say Fedor boxing against Joe "Part-time Plumber" Johnson.
or
Manny vs the #100 MMA fighter at MMA in his weight class.
Manny vs Diego "The Part-Time Tatto Artist" Gonzalez.
Of course none of these would ever happen. But at least now you've got a discussion!

But the real question everyone wants to ask, but is to pc to voice is...

WHO WOULD WIN IN A FIGHT, A BOXER OR A MMA FIGHTER?

There are no rules in a fight. There are plenty in MMA and Boxing. A fight takes place quickly and most of the time in close, close proximatry. It usually doesn't last very long, it happens in a burst. So the answer is pretty clear...
There is not one universal winner. It is between two men trained to fight. There is not the giant advantage that either has against a civilian which is, they know what to do when hit. Most civilians don't.

Simply, it comes down the the man himself, not what he is trained in.