I'm with Lyle on this - it really does depend on what you call 'great'.

Does 'great' simply mean the best, most accomplished fighter? Lots of people on here rely on statistics and numbers for that. If we take another sporting analogy, one could list the top ten 100m runners of all time by simply listing the last ten world record holders, or just the current top ten (saying that humans are bigger, stronger, better trained and with more advanced nutrition nowadays)

I'm not sure that tells the whole story, though. What if Usain Bolt had been born in the 1920's .... Would he have been faster that Jesse Owens? He would not have been the 6"5' monster he is today. Would Jesse Owens have run under 9 seconds if he had been born in 1990 and was bigger, better trained, running on good tracks etc?

There is also the element of competition... Asafa Powell has run many of the fastest times in history, but he crumbles somewhat under the pressure of a big final, while Bolt revels in the limelight and it brings the best out of him.

Even removing the so argument that all athletes today are better than they used to be (which I don't necessarily subscribe to) I think that there are other elements of 'greatness', how dominant over everyone else were they (Rocky Marciano), what was their longevity at the highest level (Joe Louis), did they transcend the sport and become mainstream (Ali, Dempsey,Tyson), did they make such an impact that legends have grown up around them (Liston)?

Of course, there's no set answer to this question, just as we will never know if Roger Federer was a greater player than Rod Laver, or whether Ayrton Senna was a better driver than Juan Manuel Fangio

Trying (!) to take the above into account, and recognising that I will have my own biases, here's my two penn'orth;

1. Joe Louis
2. Muhammad Ali
3. John L Sullivan
4. Jack Dempsey
5. Mike Tyson
6. Rocky Marciano
7. Larry Holmes
8. Lennox Lewis
9. George Foreman
10. Sonny Liston

And so many great fighters didn't make this list.

I rate the Klits and some other modern heavyweights too, but it's too soon to judge them yet. We moan about them, denigrate the quality of their opponents and say they're boring. Let's see what comes after them, as it won't be long before Wlad represents the Good Old Days

I'm sure people disagree, and I might well come up with a different list tomorrow if I was asked!.