Their have been some very good point's brought up up on both sides of this discussion. I competed in wrestling in high school and college, football in high school, competed in a judo tournament, and trained in karate. I would have to agree that the beating that a boxer takes is something that I would not want to go through on a regular basis. I was surprised when I rented an Ultimate Fighting video and saw how well the wrestlers did. Out of the first 15 or so competitions wrestling had four champions. The champions were Marc Coleman, Dan Severn, Randy Courture, and Don Frey. Virtually all the winners had competed in wrestling at some point (or had some form of grappling training). Boxers didn't win any championships and were basically being humiliated.
The other fighting discipline that did well was ju-jit-su, which relies on grappling.

Once while watching Olympic wrestling, on TV, they posted a stat which read that wrestling was the second toughest sport as far as total body fatigue. Number one was swimming. If you have never seen an Ultimate Fighting competition I suggest you watch UFC I thru XV. They give wrestling a lot of credibilty.