It does not matter whether you want to put on the latest armor for the new Crusader character, or opt to let your existing hero continue his or her exploits into Act V, Diablo 3: Reaper of Souls will definitely offer updated loot rewards, all-new class skills and abilities, game-changing features including the Mystic and Adventure Mode, as well as highly replayable content thanks to the inclusion of Bounties and Nephalem Rifts.
If you want something out of the ordinary, there is the Digital Deluxe Edition that you can take a look at, as it boasts a bunch of in-game goodies: a collection of exclusive helm- and weapon-transmogrification recipes, a loyal Spectral Hound minion, three more character slots, an in-game Treasure Goblin companion pet for World of Warcraft; and an assortment of Crusader-themed Battle.net portraits and Malthael-themed decals for StarCraft II.
The asking price? The Standard Edition will go for $39.99, while those who want the Digital Deluxe Edition will have to fork out $59.99. You do have the option of upgrading to the Digital Deluxe Edition from the Standard Edition preorder by paying the difference.