I just had an extremely informative discussion with a PO at NSF about revising my proposal. One of the most useful tidbits was that it is actually BAD with NSF to do the whole "introduction to resubmission" thing with all your point-by-point revised items. With NSF, that can call attention to the negatives and keep reviewers (who are frequently different people than reviewed your grant first time around) from recognizing the awesomeness of your revised proposal. The advice was just to revise according to the overall comments and let the better proposal speak for itself.
I am incredibly lucky to have been hired by a department who wants to let me do my 'unfocused' science. They especially like that I don't do any one thing in particular. BONUS! We'll see how it all turns out over the next 5-7 years.
You can email me at: chemicalbilology at gmail dot com