Blizzard has unveiled a new "Paragon" system coming in patch 1.04 of Diablo 3, aimed at adjusting the Magic Find system and end-game content. The Magic Find tweaks are engineered to deal with feedback that some users find swapping gear frustrating or unfair, and Blizzard has already been pretty frank about its end-game.
A blog post from game director Jay Wilson details the new system. Once you hit level 60, your experience from killing monsters will go towards Paragon levels. The game has 100 Paragon levels in all, which reward you with extra Strength, Dexterity, Intelligence, and Vitality, along with 3% Magic Find and 3% Gold Find. You'll also get an increasing border around your character portrait to show off your Paragon status. Blizzard says that the time investment to get to the upper Paragon levels is roughly the same as the time required to get to level 99 in Diablo 2.
It will also cap Magic Find and Gold Find to 300% (sans Nephalem Valor), so if you reach Paragon you can keep wearing your Magic Find gear while grinding for higher levels, but won't have to use that special gear once you hit level 100.
Blizzard hasn't outlined a date for the upcoming patch yet, but promises more details soon.