WordNet (r) 3.0 (2006):

maven
    n 1: someone who is dazzlingly skilled in any field [syn: ace,
         adept, champion, sensation, maven, mavin,
         virtuoso, genius, hotshot, star, superstar,
         whiz, whizz, wizard, wiz]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "maven":
   adept, amateur, arbiter, arbiter elegantiarum, arbiter of taste,
   authority, bon vivant, cognoscente, collector, connaisseur,
   connoisseur, critic, dab, dabster, dilettante, epicure, epicurean,
   expert, good judge, gourmand, gourmet, judge, master, past master,
   professional, proficient, refined palate, virtuoso