I think Al Gore should announce that not only is he endorsing Obama, he's joining Obama's ticket as his vice president.  I'm only half-kidding, hear me out...
I actually think it's true that Al Gore doesn't want to run for president.  Politics is ugly and horrible and the only point of the whole thing is to gain notoriety, respect, money and influence - all of which Al Gore arguably has more of now than most presidents will ever have - but without any of the downside.  Since re-joining the civilian population he's won an Oscar and a nobel prize, started a TV network, some environmental investment funds, become a cultural icon the world over, made millions and everybody loves him - it's beautiful...so why mess with it?
Because right now Al Gore has the chance to completely circumvent the entire political system, unite the democratic party, accomplish more of his personal agenda than he ever thought possible, and make the United States the leader in sustainability around the world.  
He makes the ultimate sacrifice by taking a backseat to Obama, simultaneously making himself the most beloved leader in modern times and making Barack Obama the Exalted Leader of the United States.  Gore actually manages to upstages Obama in the uniter department and does so with near-martyrdom humility and sacrifice.  I mean, even the Evangelicals love this guy.
But, he's not stupid.  No one does this kind of thing for purely altruistic reasons.  Gore's smarter than that, and his years of political failure are behind him.  He's got some perspective on the whole thing now, and he's cracked the American political code.  Business and politics are the same thing in this country, he realizes - there's nothing significant you can accomplish in business without politics and there's nothing significant you can accomplish in politics without business.  He knows that without the pressure and scrutiny of being president he actually has the time and opportunity to manipulate the system in this country with almost God-like power.  He needs only to call on his 8 years of VP experience to know just how much he can get away with.
He has a working majority in congress that he's personally created, ties to the business community that he's spent the last 8 years cultivating, the president in his back pocket and he's widely considered the best human on earth.  With this unrivaled power he will be able to completely change the entire economy and infrastructure of this country during the 8 years of the Obama administration.  And, who knows, maybe he just decides to succeed his protege in 2016, and live out some of his golden years in the oval office of the country that he's basically created.
Here's how it would go down:
1.  They announce an Obama/Gore ticket and the race with Hillary is immediately over.  The democratic party suddenly has the best of all possible worlds, and the entire country - Democrats, Independents, Republicans, Christians, Muslims, Jews, Blacks, Whites, Asians and Hispanics all gather around our great new leaders.  They form to create the Megatron of voter coalitions, which leads to a landslide victory like the world has never seen for the Democrats in November.
2.  The message is powerful, and by the midterm elections in 2010 the Democrats have more than a working majority in congress - they have a lead on the Republicans that will take years, perhaps decades to overcome.
3.  Our government finally has the power to get things done, and the entire country is behind them for the first time in my lifetime.
The world rejoices.