I'm delighted that Alex Long of Oklahoma City University is a leading candidate. Anyone who's creative enough to look at citations to songs in legal scholarship deserves consideration. (By the way, Alex, in the next iteration of your article, you might cite my invocation of The Clash's Joe Strummer's statement that "if you ain't thinkin' about [hu]mans and God and law, then you ain't thinkin' about nothin." It's not a lyric, but it fits with your overall interest in articles that invoke musicians' insights.) Paul Butler's another great candidate.
All of this leads the social scientist in me to ask: is there a way to quantify coolness? As a notorious square, I'm not sure I'm even qualified to talk in general terms about how to define cool. I would submit, however, that appearing in pop culture is one (one--not the exclusive) indicator of "cool."
I would think that one of my favorite law profs, Randall Kennedy, has got to be on anyone's short list. As discussed here earlier, he was quoted in Cosmo. Even more importantly, there was an episode of Boston Public devoted to his book on the N-word. Jessica Litman of the University of Michigan was quoted in Rolling Stone. Again, I'm looking for objective indicators of coolness--and I think that being quoted in leading pop culture magazines is a good indicator. Time for our friend and Money-Law superhero John Doyle of Washington and Lee Law School to compile some stats on this....
Seems to me that coolness is associated in part with marching to your own drum. So we shouldn't care too much about who's acting in ways that others approve (though approval of others obviously is somewhat important--see above). That's why I think coolness is not necessarily associated with youngsters. Maybe older people are cooler than younger. At a legal history conference in Austin some years ago, I was wandering around downtown on Halloween and one of my friends (I won't embarrass him by naming him but I will say that he's an awesome legal historian), said "groovey!" Ah, just the perfect phrase for that evening.
How much is coolness related to language? It's less important whether your writing or speech sounds like it's been run through the Ali G translator--er, Da Ali G translata--than if you have some new, humane ideas, isn't it? If you want to see a work informed by hip hop and rich with insights on law and humane ideas, I'd recommend Imani Perry's wonderful Prophets of the Hood.
Of course, maybe in deciding on something like "coolness" we ought to be using some less easily quantifiable factors: like who's producing innovative scholarship? Our own Jim Chen wrote what my favorite librarian (who is notoriously critical of scholarship) called the best article she's read in a long time. And Jim's facility with pop music makes him cool; I actually laughed when I read this entry.
In addition to Randall Kennedy, Jessica Litman, and Imani Perry, let me nominate Mitch Crusto of Loyola Law School, New Orleans. Mitch has written some terrific work on race in the nineteenth century. Take a look at it--it's, well, cool....