Blizzard COO Paul Sams mentioned at BlizzCon that they haven't yet ruled out Diablo 3 for consoles. "We've met with the major manufacturers, and they've made some pretty compelling arguments," Sams said. We can safely assume he means Sony and Microsoft, because it's nearly impossible to imagine this game running on the Wii.
Sure, it's what Blizzard says about all of its projects as they relate to consoles and yet, here we are, with nary a Blizzard console game in sight. But Sams did reiterate Blizz's interest saying that we will be seeing its games on consoles in the future. "Whether that's three years from now, five years, I can't say," Sams noted. "But I have no doubt that we'll be making games for consoles."