I can understand something such as World Of Warcraft needing online since it's intended to be an massively huge online multiplayer experience. On the other hand from my time with the Diablo 3 beta I simply don't see the need for multiplayer with this outside of perhaps grouping together to co-op on dungeons, auction house, and potentially PvP stuff. I'll have my hands on Diablo 3 this Tuesday so I'll give my review on the game itself soon enough.
Listen. Think. Rant.
NFL = New England Patriots (AFC) & Minnesota Vikings (NFC)
MLS = New England Revolution (East) & LA Galaxy (West)