No - he's a Senator. For VP perhaps, but not President...then again, with a sitting Dem Governor that also makes that a drawback.
RE: "No - he's a Senator."
The track record for Senators in Presidential elections is pretty shoddy (not since Kennedy in '60 has one gained election to the White House), but in a primary race as fractured and disparate as the one awaiting the Republicans in '08, you go with the best that you can get.
What good Republican has a better chance at election than Sununu or Pensylvania Senator Rick Santorum? Rudy Guliani and George Pataki-- way too liberal (he won't even condemn partial-birth abortions). George Allen, Bill Owens-- no name recognition (and Owens is so right-wing he makes the President look like a Kennedy).
I can't think of any truly electable Republican candidate at the moment, unless Secretary Rice deserves to run. Please, God, let Condi run!