My Prediction:

that it will be Flaherty versus Menino starting tomorrow, I don't think Hizzoner will get 50% of the vote today, but don't take that to the bank.
Sam Yoon is running an interesting campaign, if I lived in Boston I might vote for him, but his election day battle plan depends on rousing thousands of new voters and ushering them into the polling stations. This is a dubious proposition at best, in Boston at the ward and precinct level the old politics rules the roost, the cohorts that marched for Barack Obama in 2008 are not necessarily passionately engaged with the question of who gets to be Mayor.
Therefore the decisive constituencies will be the buzzcuts, their wives and such minority groups as are organized for a city wide political fight.
Given that, I think it'll be Flaherty versus Menino with Menino clearing the boards come November unless some gale from out the shoals of scandal hits the Mayor.
Of course, a good old fashioned upset tomorrow does feed my need for "bloggable chaos", so here is to chaos!
:D