What is it about some guys??

I have been talking to a few of my girlfriends and we were discussing that essence that some guys have that make them so attractive. It has nothing to do with their looks.. or even with their personality.. it is just with the way they carry themselves. I don't know what it is or how to explain it, but any girl will know what I am talking about. You can tell instantly, just by the way a guy walks if he has IT or not. Its the air around him, his mere presence, the way everyone around him takes notice when he is there... its his sheer confidence. And I mean true confidence, not cockiness. One that is truly confident does not need to boast. A good is example is any "leader" of a group. The leaders usually always have it. I don't know if this comes natural to some people, or if you learn it... either way some have it and some don't. You would think whatever this is, would come with physical attractiveness.. but that is not the case. There are plenty of extremely attractive guys that do NOT have it, and there are some not so hot guys that do have it. Its the guys that seem to always land girls appearing to be out of their league. One of my good guy friends, who will remain nameless, is a prime example of someone who has it. He's attractive, but not super hot... he has a great personality, but not one that would necessarily charm girls... but he has IT... that presence... that confidence... that magnetic pull that you cant seem to resist.