Palin would be fine. She’s been in office for 2 years, has lots of local experience, her husband is not a pol but works as an exec on the North Slope and is part Yupik (a local Native American group), and she’s clearly aggressive but at the same time not so abrasive that nothing could get done. Jindal might be fine, but he’s really, really new.
The most successful US presidents have been governors (well, some of the worst have also been governors - think Carter and Clinton), but in any case, state governors generally have a much better chance than senators of getting elected to the presidency.
BTW, unless I am **much** mistaken, this will be the first such contest, senator vs. senator, in US history. There's no track record on which to bet, other than that senators have historically made mediocre-to-lousy Presidents.