Blizzard have released the full patch notes for Diablo III v.1.0.5, which adds a new monster power system that allows players to control how challenging enemies are on different difficulty levels. Upping their health and damage to different "power levels" (over 9000?) will result in boosted XP, as well as increased magic find and gold find for Inferno players.
A new event for level 60 players will also be included, alongside a big fat nerf for the Trail Of Cinders skill rune and numerous tweaks. You can read the full patch notes on the Battle.net forums... unless you're too busy playing the exceptional Torchlight II.