Undoubtedly, he is the best, most versatile mountain trail runner there is, equally at home on a Vertical Kilometer course, or a technically demanding 100 miler. However, he also leads 5.12 trad climbs, solos long alpine routes, has speed ascents on everything from the Matterhorn to Mount Everest, has won every imaginable skimo race, and occasionally skis steep chutes, like the Fiva Route on the Troll Wall in Norway.
He's got my vote! Read this excellent profile (and book review) in The Guardian.