Some of the qualities I have found admirable in the atheists I have met is their knowledge of science. It always seems no matter who I'm talking to, if they're an atheist their knowledge of science is on point.
I like their proclivity to debate as well. In a good way though. I'd rather spend my time discussing or debating with an atheist than someone in a cult or aberrant sect of some religion. Due to the fact the atheist is usually a far better debater