The greatest conductor?
The Guardian's Ed Vulliamy profiles Valerey Gergiev, terming the Russian maestro "the greatrest conductor of his generation":
http://www.guardian.co.uk/music/2009/sep/20/valery-gergiev-london-symphony
I would call Gergiev the greatest living throwback to the generations of Mengelberg, Toscanini, Stokowski, Karajan, Bernstein and Solti – figures who imposed a personal sound and grand scale on orchestras, and who presented the public with an oversized personality. Like them, Gergiev can be intoxicating leading one of "his" ensembles (the London Symphony, the Mariinsky Theater Orchestra) in a big, brash score. Basically, he has upgraded the Soviet-style leviathan orchestra into a more refined and fleeter-footed 21st-century model – the ultimate Shostakovich machine.
But I can think of many composers, whole periods and schools of music, from Bach and Mozart to Debussy and Bartók, that I would rather not hear given the Gergiev treatment. And that list is long enough to disqualify him, in my book, as "the greatest."