3. Popular vote | As this article points out, the Clinton campaign's projections of being in the lead in the popular vote rely on including Michigan (where Obama's name wasn't even on the ballot) and excluding the caucuses (which don't release official figures in terms of votes, but which the Obama campaign tended to win significantly). Clinton's last big shot to take the lead with the popular vote was in Indiana. In winning be such a narrow margin that chance is over.

4. Florida and Michigan | These two crucial general election states got a telling off from the party for trying to bring their primaries forward and as a result were stripped of their delegates. Hillary wants to include these delegates (she won both by large margins, though hers was the only name on the ballot in Michigan), even going so far as to suggest that all those votes that didn't go to her in Michigan can be counted as for Senator Obama. However, Politico.com recently revealed that even if the Obama campaign were to fully embrace this suggestion, it still wouldn't provide enough delegates for Clinton to take the nomination.

5. Campaigning | While Hillary has admitted to loaning her campaign $20 million, Barack has completely shifted his campaigning strategy. In the next couple of weeks he is spending time in Michigan, Florida and Missouri. All are big general election states, and the lack of a contested primary in the first two meant that the Obama campaign has not yet laid out a ground organization there. Obama's focus is shifting from the primaries to the general election.

The only thing left to hold out for if you've got money on Senator Clinton is the hope that some massive new scandal develops which makes Obama unelectable. Given that this is day 9,293,291,03... of the primary season that seems pretty unlikely.

With all that in mind the race changes direction. There's the question of when Hillary will finally call it quits and we may find some clues to that tonight in her victory speech remarks (attacking Obama = carrying on), and margin of victory (polls have put her 30 points clear, anything significantly under that will make it hard to stay in the race). It's been suggested she may be holding out as a bargaining chip to get something from Obama (like the Vice President nomination or his adoption of one of her key policies).

There's also the question of whether the drawn out primary season has harmed the Democratic chances in November.
Most excitingly of all, there's the question of who the GOP and Democrats will pick as Vice President nominee. Expect posts giving odds on different possible candidates for this in the next few days. In the meantime, why not post your suggestions below.