You can see the details about the collector's edition here:
CATACLYSM EXCLUSIVE BEHIND-THE-SCENES DVD:
• Over an hour of developer interviews and commentaries, discussing the game's development from early design through finished gameplay.
• The Cataclysm intro cinematic and major content patch trailers complete with Director's Commentary.
• A special Warcraft retrospective examining the rich gaming history of the Warcraft universe.
COLLECTOR'S EDITION SOUNDTRACK:
• Seventeen epic tracks from Cataclysm, featuring exclusive bonus tracks.
THE ART OF CATACLYSM:
• 176 pages of art, featuring never-before-seen images from the archives of the Blizzard Film Department and the World of Warcraft development team.
• Progressive visuals from every stage of development - from early concepts through to finished, detailed art.
WORLD OF WARCRAFT®: CATACLYSM™ PC/MAC GAME:
• The full World of Warcraft expansion set on CD-ROM and DVD-ROM.
WORLD OF WARCRAFT TRADING CARD GAME STARTER PACKS AND EXCLUSIVE CARDS:
• One 60-card deck from the new Wrathgate series featuring two extended art cards and visuals from several of fantasy's top creators.
• Two exclusive hero cards, marking the first appearance of goblin and worgen heroes in the WOW:TCG.
• One full-sized rule book to teach you how to play.
EXCLUSIVE IN-GAME PET:
• He may not be a breaker of worlds... at least not yet... but Lil' Deathwing will still aid you in your titanic struggle to save Azeroth from his much, much larger counterpart.
• A special-edition mouse pad depicting Deathwing menacing the ravaged continents of Azeroth.