The following achievements have been added:
    Deeds of Valor: Die with a level 60 Hardcore character
    All For Nothing: Die with a level 60 Hardcore character of each class
    Born to Grind: Die with a level 60 Hardcore character fifty times
Demon Hunters can now craft and purchase arrows from the Fiendish Fletcher in town.
(Arrows are required for all ranged attacks and abilities. Arrows stack in groups of 30.)
To encourage players to appreciate the rich narrative flow of full acts during subsequent playthroughs, casting Town Portal now removes one stack of Nephalem Valor.
Following the success of averaging Magic Find in multiplayer games, players' DPS will be averaged to help facilitate a balanced group play experience.
When your follower dies, you have to resurrect them in the same manner you would resurrect fellow players. They will not automatically respawn.
Patch 1.0.4 Class Balance Changes
General
    Treasure Goblins now have 50% more health and received a 25% increase in movement speed
Monks
    All unique monk weapons now have a 0.1 attack speed reduction
    After death, you will now spawn with 0 spirit instead of 75
    The duration of Serenity has been reduced from 3 to 1.5 seconds
    Fists of Thunder proc rate reduced by 25%
Witch Doctor
    Summon Zombie Dogs and Gargantuan cooldowns increased from 60 to 120 seconds
    Zombie Chargers mana cost increased from 140 to 200
    The mana pool will now be capped at 300 max mana
    Max mana item affixes have been eliminated
Demon Hunter
    Smokescreen will now have a 0.2 second casting delay upon activation
    Primary skills no longer generate Hatred. Hatred regeneration can now only be increased using hatred regeneration items a la Witch Doctor
Patch notes that would enrage community xD