This is obviosuly an American discussion. I find it interesting to see the definitions of manliness being proffered; in Europe one of the most popular actors is Vincent Cassell, who often plays a tough guy, but he is almost always a tough guy with something extra, usually very articulate, stylish and prone to philosophy, with a sense of the un-necessariness of his situation. Ken Watanabe is a great Japanese tough guy, almost autistic but with a strong moral sense in an often terrible world. But I'm sure we all agree that Manliness is almost by definition a term which deliberately limits itself. For me, at least when thinking of American icons, Robert Redford is everything a man should be, the embodiment of a better time; never a coward, always hardworking, measured, courteous and civilised but with an independence and dignity few possess.
Thinking of today's ideals of masculinity, I can understand how young men beginning to make their way in the world can be confused or even perverted, surrounded by a new breed of "musician" whose only contribution to society seems to be to brag incessantly about what they've taken from it. Turn on MTV any day of the week and one can be forgiven for wanting to give up on anyone under 25 year old. Right now we have so few examples of integrity, from any sphere of life, be it business, politics, sport or "culture", that it is no wonder the membership is forced to look back to their father's generation for examples of how to live.
So I would say that, right now, someone like Moby would be a decent example of manliness; intelligent, articulate, creative and productive, with a sense of his responsibilities.