Re: Most effective discipline in the clinch?
Kind of cheating beacause it isn't a sport in and of itself, and is based around wrestling, but dirty boxing. You need to learn to use the tieups from greco or freestyle to transfer to punching people, not just takedowns.
So with all that said, greco basically, although you need to have the basics of freestyle or folkstyle, which all good US greco guys will, in order to use the legs for sweeping, which Couture and Lindland both do well.
Judo also works, but most judo guys use it simply as a means to a takedown, not a "clinch and pound" style.