Bill Daley has been on his way out as White House chief of staff for some time now, but he's now out for good, to be replaced by OMB director Jack Lew. I'm not going to say that WH CoS is as important as who gets presidential nominations, but it's awful important, and it's not entirely clear that the difference between Daley and Lew couldn't be close to as large as the difference would be between Barack Obama or Hillary Clinton as president.
Beyond that, a nice point over twitter from Ryan Lizza, who notes that "Patience pays. Both Gene Sperling and Jack Lew, who were passed over for top WH jobs during '08 transition, are now NEC dir. and WH CoS." That also suggests that for all the attention that we pay to these decisions in November and December every four or eight years, the first WH team or cabinet isn't likely to be the last one, and may not be the most important one. And an excellent post on the transition from Ezra Klein, who reports that Lew is as popular in both the White House and Capitol Hill as Daley was not.
Meanwhile, OMB is a very important job, which will now have to be filled once again. And that one requires confirmation, so there's that headache. What I don't know: what can't an acting director do that a confirmed presidential appointee do? I sort of think that with OMB the answer is no very much, at least by statute, but that an acting director won't have the clout within the executive branch that a confirmed director would have, but I don't actually know the answer to that one. See too Stan Collender's comments about who can serve as acting director, as well as his speculation about who will get the job.