The real question though is what happens if Obama does win by a few points in Iowa.  Given Hillary has been ahead in most polls both in Iowa and nationwide, the inevitability meme is playing harder than ever.  I have to think that a loss in Iowa hurts her.  Whether its enough for Obama to get a big enough bounce to beat her or get real close in SC and NV (and NH IF it still takes place after Iowa and they don't act like a bunch of tools and move into December).  I do think IF NH moves and Obama wins Iowa, South Carolina gets REAL CLOSE REAL FAST (I think most of the support that left Obama for Hillary was soft and remains soft and will go with the candidate with the momentum.  If Obama shows he is surging, he will get most of that back... if Hillary wins Iowa, she will keep it and get more) and probably favors Obama.  

Long story short, If Obama wins Iowa by a few points as you say may happen, then the race tightens (unless Hillary gets blown out of the water in Iowa, which I don't think will happen) and it probably comes down to Feb 5 to see who the the Nominee is.  If Hillary wins by 5-10 points, the nomination is probably over (stranger things can happen on Feb 5, but I doubt it) unless Al Gore has gotten into the race and can't do Iowa (In which case it is Gore vs Hillary with Obama and Edwards losing a majority of supporters to Gore, IMHO).  Jan 3 looms as a day of interest, and I see all candidates in until Feb 5, regardless of their finish in Iowa.