MSNBC reporting now that David Souter is stepping down from the Supreme Court. Holy smokes. What a week.

UPDATE: Discussion threads at Daily Kos (1, 2), Talking Points Memo, MetaFilter, MyDD, Politco. My commentary is limited entirely to silly quips on Twitter at the moment, but I sincerely hope Obama recognizes that Supreme Court appointments are not a time to play it safe. 60 senators (hey Arlen), height of his popularity—time to go nuts.

More tomorrow.

UPDATE 2: Already seeing a lot of buzz around Sonia Sotomayor.

UPDATE 3: More names from SCOTUSblog: "The three obvious candidates are Elena Kagan (SG), Sonia Sotomayor (CA2), and Diane Wood (CA7). The sleeper candidate is Michigan Governor Jennifer Granholm."

UPDATE 4: Wikipedia is on the case.