The End Is Near: Wherefore The Polls?

So it's beginning to look and sound as if Hillary will leave the primary race by June 4 after all and not take it all the way to the convention.
This has been a remarkably unusual election year, without recent or comparable precedent for the
historical nature of the two leading Democratic candidates, their contrasting strategies — how could there be a precedent for Obama's online fundraising? — and the drug-outedness of this contest.
Still, John McCain, who as the Republican nominee has had a clear field for months, flatlines in poll after national poll at 45 percent, seldom less, seldom more.
All the liberal commenters seem to agree Obama will get a big jump in the polls once Hillary is gone.
My question, purely for speculative fun, is how much will he gain?
And like Markos at Daily Kos, I won't bother with researching my entirely unscientific guesstimate.
I think the first polls after Hillary exits will show Obama with a 60-40 advantage.
The CW (conventional wisdom) is that national polls mean nothing this early in the game.
There's all the Swiftboating expected against Obama, and the entirely plausible scenario that he could stumble, maybe really badly.
But I still think this year's election will be a landslide for the presidency and both houses of Congress and I believe the Republicans know it.
But, of course, that's what I want to believe.