The only real surprise tomorrow would be if it's not super-close. So, does it really matter whether Clinton leads by 75 or 25 delegates? Suppose it's even closer, does it matter which candidates has a 20 delegate lead? I say, yes, it absolutely does matter.
At some point, there will be intense pressure for the party to coalesce around one of the front-runners. Exactly when that pressure will begin will depend on several variables, including the rate at which McCain approaches a mathematical lock on the Republican nomination and at what point McCain's rivals drop out. That pressure will also be dependent on one of our candidates building a small, yet sustainable lead in the hard delegate count.
The mechanism by which we will coalesce is two-fold. One, voters may recognize one of the other candidate as the front-runner and begin to break in their favor. Certainly, I don't expect either candidate to start winning 65%+ of the vote in many states, but a 55%-45% national split will start to push the race's parity beyond the breaking point. Secondly, whether the voters make a decisive switch or not, there will be a lot of pressure for the super-delegates to align with whichever candidate can build a small lead.
Now, I don't expect either process to begin on Feb. 6th, but the Super Tuesday results will set the context for the weeks leading up to March 4th. The contests in that period - primaries in Louisiana, D.C., Maryland, Virginia, and Wisconsin; caucuses in Nebraska, Washington, Maine, and Hawaii - seem likely to result in a net gain for Obama. If Obama can keep things close after tomorrow, then he can use these states to rack up not just momentum, but a lead going into March 4th. By then, McCain will likely have spent several weeks as the presumptive nominee and Democrats will be spoiling to get the primaries over with. At that point, front-runner status will mean a lot, but only if either of the candidates can achieve it.