My guess (and that's all it is) for how things will shake out today is that Hillary Clinton will do well, winning the states she's supposed to and most of the presumed toss-ups. Barack Obama may come close in California, Connecticut, Massachusetts, and even New Jersey, but my gut says he probably loses them all (though, as an Obama supporter, I'd be delighted to be wrong). In other words, Clinton scores a solid victory and establishes a significant, though not insurmountable, lead in delegates.
But while much has been made (and rightly so) of the extreme difficulty for Obama of having to compete simultaneously in 22 states with a well-known quasi-incumbent such as Clinton, there is, I think, a silver lining: specifically, that, however many states Clinton carries (assuming it's not an utter blowout), today will feel like a single "win" in terms of the broader narrative of the campaign.
Meanwhile, the primaries that are scattered throughout the rest of the month are generally Obama-friendly and take place not more than two or three per day: Louisiana on Saturday; Maine on Sunday; Virginia, Maryland, and DC next Tuesday; and Hawaii, Washington, and Wisconsin a week after that. Obama ought to win most of these, and could even run the table. Though it might not make any difference from a delegate standpoint, if Obama strings together three or four winning days in a row, it'll be hard to shake a sense of gathering momentum. (And, in politics, perceived momentum often translates into the real thing.)
To put it another way, if the Super Tuesday states were stretched out over a week or so, and Clinton won New York today, followed by California on Saturday, followed by Connecticut, Massachusetts and New Jersey next week, she'd probably knock Obama out of the race. As it is, he can lose all those states and live to fight another day.