First, Obama isn't playing for a win on Tuesday. Just something that approximates a stalemate. (I'd say that means carrying 8-10 states and 45 percent of the delegates up for grabs.) The old conventional wisdom was that a long, drawn-out fight benefits Hillary, since all her natural advantages (fundraising ability, name recognition, establishment support, access to free media) will kick in once Obama's momentum fades. But, increasingly, I think a drawn-out fight favors Obama. Not only is he raising money at a phenomenal clip ($32 milion in one frickin' month!), but Clinton-fatigue is starting to take its toll. (Such is the nature of "fatigue" that it only gets worse over time.) Conversely, people seem to like Obama more the more they see him.
The other thing to keep in mind is that, if Obama can just survive February 5, then he's back to a schedule that's perfectly manageable for someone with so much money and such a large organization. There's not a day on the primary calendar between Tuesday and the convention that has more than four contests scheduled. Even on March 4, which the Post says could be a decisive day, Ohio and Texas are really the only two games in town. (Vermont and Rhode Island also vote that day, but, you know, they're Vermont and Rhode Island.) And there are two weeks between March 4 and the previous primary day. Since, as MacGillis and Kornblut point out, Obama tends to do better the more time he can focus on a specific state, I see this slightly benefiting him.
Bottom line: It may be to Obama's advantage to have one massive primary day (Feb. 5) followed by a bunch of two-state affairs, since, if he can just survive the former, he's got a great shot in the latter. Conversely, it would have been much trickier for him to have several six- and eight-state primaries every week, since it would have been impossible to focus on one or two particular states but, unlike February 5, the press wouldn't keep giving him a pass.
Update: A reader points out that, if this becomes a delegate race, Obama can't afford to dig too deep a hole for himself--it's too hard to make up ground in later primaries since they're not winner-take-all either. Good point. If Obama wins 45 percent of Tuesday's delegates, he'll be facing about a 200-delegate deficit. He probably needs to keep it closer to 100, which would mean winning about 47.5 percent of delegates. Still eminently doable (even likely), but worth keeping in mind...