It's absolutely true that Dems are celebrating the demise of the Republican party way, way too soon. There's little doubt that the pendulum will swing back to the right at some point, but there's some key issues to tackle before that can happen.
First, a clear leader is going to need to step. And where this gets really interesting is that this leader is going to need to appeal to both the base and the elusive swing voters (those that are either independent or are willing to vote against their usual party affiliation). Right now the party base won't vote for the candidates that appeal to swing votes that could be peeled off of the Dem party (think Jon Huntsman or Tim Pawlenty).