The editors at Real Clear have been in the science media game for 3 years, so they have a good understanding of who writes and what styles are, and compiled a list of their favorites. They get pretty diverse too, because science media is still corporate-driven but there are at least a lot more of them than there were 6+ years ago when Science 2.0 went online for the public.
National Geographic is represented - three times, actually, since they now own Scienceblogs and have their own blogging group - with Carl Zimmer and Ethan Siegel and Ed Yong. Ars Technica makes the list, as does Mo Costandi at The Guardian (I follow him on Twitter, so I agree), Wired (twice), and Slate.
Oh, and Science 2.0 also - as the only non-corporate media group. I am in there, sandwiched comfortably between Ed Yong and Radiolab's Robert Krulwich, which is a pretty good place to be.
Thanks for recognizing independent science media, Real Clear!