It depends on the trip. We are at the beach right now and one of the things that makes it a beach trip to us is eating all the local foods. Couple of great pizza places, a really good Italian place, good sub shops, seafood for the wife, etc. When we were planning for this trip, we brought breakfast stuff and snacks for the kids. We ate out every lunch and dinner on this trip.
When we go to the lake, we bring food for every meal. Chicken breasts, stuff for tacos, hot dogs/hamburgers/sausages, deli meats, etc.
Going to Florida for a couple weeks in the winter we usually don't bring much, but we buy from the Publix supermarkets down there and cook most meals... but we also have local spots we try to frequent when we are there.