The Standard Edition will grant access to the game for $39.99, while the Digital Deluxe Edition at $59.99 includes spectral hound minion for Diablo 3, a treasure goblin pet for World of Warcraft and portraits for StarCraft 2. Finally, the Collector's Edition includes everything from Digital Deluxe, plus an Angel of Death mouse pad, art book and behind the scenes Blu-ray/DVD.
Oh wait, there's one more edition, the Soul Asylum edition... but that'll only cost your soul*!
*No, there isn't a Soul Asylum edition. It involves a runaway train that's never coming back.