Who is or was the most intimidating opponent, past or present?

Mike Tyson. Period. I swear you could see a little brown spot develop in his opponents shorts every time he fought! Until he lost to Douglas, he was one unbeatably nasty SOB.

Haha - yea, I can still see that little brown spot on Michael Spinks's shorts

Mike Tyson and probably George Foreman.

You could probably throw Frazier in there, right after Foreman.

I have never seen Joe Frazier as a very intimidating boxer. Sonny Liston is superior in that category, isn't he?

Probably right, but I seem to remember Frazier being quite the intimidating figurer in his day, until he lost to Ali. Of course, I was a kid back then, so my memory of Frazier might be warped a bit.

Yeah Tyson is a good call, but not only heavyweights are intimidating, my selection will be Roberto Duran and Iran Barkley( man he was a ugly hard s.o.b)

Good get with Iran Barkley. I totally forgot about "The Blade".

Yes, I would second Barkley too. He had a very mean looking, fixed stare, an almost forlorn look like you'd expect to see on the faces of death row inmates.