Modern anarchism probably isn't a coherent entity, so it's hard to say whether Hakim Bey or John Zerzan are relevant or not. (I'm assuming here that the term _relevant_ carries with it a notion of significance.) In any case, even if they are lunatics, they may interest people who are not lunatics who may later accomplish something suitably sober and reasonable, just as the apparently praxis-challenged Bookchin may, although the latter seems less likely to me since Bookchin is much grumpier than the other two. But let a hundred flowers piss in the wind.
> A good portion of Bookchin's essay attempts to define what it means to be
> an anarchist, which he contrasts with being a Luddite, mystic, or
> solipsist. It strikes me as an important thing to worry about for those
> with any interest in anarchism, especially if what it means to be an
> anarchist is contested. ...
In some worlds, it may be important, but in the world of anarchism (as I see it, of course) Bookchin is just one more person who describes himself as an anarchist and has an opinion about what anarchism means. I'd be a lot more worried if the idea of what anarchism means _wasn't_ contested.