By One of the worst kept secrets of recent times is that Blizzard were apparently developing a third game in the Diablo franchise. The purchase of the Diablo3.com domain seemed to back that up. And recently they have added a Diablo 3 section to their website.
Coupled with the previous announcement of Starcraft 2 it would appear that things are looking good on the Blizzard front.
I have been looking at Diablo III on the Arreat Summit. Looking forward to it. I've started playing Diablo II again too.