No personal experience with repairing a flooded house, but from what I understand and have read, pretty much everything that got wet will need to be replaced. Apparently, this is especially true for wallboard/plasterboard. It will not dry properly and will develop one or more types of mold some of which can be a serious health hazard(even if on the outside it looks OK, in the wall it can be very bad).

Our local TV stations have been running advertisements for flood insurance. Most, if not all, homeowners insurance policies in the US do not cover flood damage, so your on your own unless you buy a separate policy.