It seems to me that whatever happens in Iowa, Mitt Romney can't afford to lose New Hampshire. Despite it's vaunted independent spirit, candidates from neighboring states have a built in advantage there. Since 1960, when John Kennedy of neighboring Massachusetts won the primary, whenever a candidate from a neighboring state has been in the race, he's won the primary. Here's the tally:
1960 John F. Kennedy, Massachusetts
1972 Ed Muskie, Maine
1988 Michael Dukakis, Massachusetts
1992 Paul Tsongas, Massachusetts
2004 John Kerry, Massachusetts
1964 Henry Cabot Lodge, Jr., Massachusetts
In fact, the only candidate from a neighboring state to lose the New Hampshire primary was Howard Dean in 2004, but this is the exception that proves the rule since he lost to John Kerry of Massachusetts.
This pattern of favoring neighbors, especially from Massachusetts, doesn't seem too surprising. According to the 2000 Census, only 43 percent of the residents of New Hampshire were born there and approximately 25 percent were born in Massachusetts. That latter number would be even higher if you included people who emigrated from Massachusetts but were not born there.
In addition, most New Hampshirites live in the southern part of the state where most television stations come out of Boston. Though I can't find the exact figures, the circulation figures for the Boston Globe in New Hampshire make it very competitive with the Manchester Union-Leader.