The last two years we've been going to our denomination's yearly family camp meeting at a beautiful campground in the middle of nowhere. It is definitely the best family vacation that I've ever gone on as a child or adult. I love it because it's very God centered, but not so structured that you don't get some family chill time. They have seperate services in the morning after breakfast for adults and the children, and then a family service in the evening. They usually have a music evangelist, as well as a speaker of some sort. In the children's services during the week they also learn and practice a song to perform at the 'big' Saturday night service, along with the teen choir that preforms all week. They have a big dining hall for all the meals, as well as a little 'snack shack' for during the day. The campground is on a lake, so there's swimming and canoeing during the day, along with an indoor pool (both have lifeguards). Another really great aspect is the affordability of it. Cabin rooms are about $100 for the week, and adults eat for the week for $100, and children are $50, so families that might not be able to afford a traditional family vacation are able to get one without going broke.
It's been 8 weeks since we got home from it this year, and I'm already looking forward to next summer.