The bill will pass.
Public Option will be pared down to a meaninless plan
Healthcare will be upgraded in future bills
Agreed. Only 16 Dems are up for re-election in the Senate next year, mostly from "safe" (read: gerrymandered over the past three decades) districts, so there's easily enough support to pass some version of this on a straight floor vote.
I doubt a Republican-mounted filibuster would last, or be effective: they have exactly 40 Republican Senators (not counting Lieberman, who is again flirting with political suicide by hinting he'd support one).
Two guesses to any Republicans here on how they think most media outlets would portray a Republican filibuster that drags the government to a halt for a few weeks... (the word, "obstructionist" comes to mind). And if a single Republican in the Senate caves to pressure at home, or is tempted by some "tweaking" of the bill - paring down the public option, or adding a 'trigger' or whatever - then the filibuster is over.
I think a lot of people are forgetting that the Democrats are primarily answerable to a base of voters that are probably more liberal than the Senate is, and with groups like MoveOn.org on their backs, and the endorsements of the American Medical Association (AMA) the American Cancer Society, and AARP providing political cover, it seems very very likely that they're going to the mat for this.
(Reality check for me: Democrats have a history of snatching defeat from the jaws of victory, so nothing is sure...)