I think a cruise would be great for a family, and most larger lines (ie Royal Caribbean) do a great job of coordinating activities for all ages. You and your children will have a lot of time apart and together which makes for a perfect vacation. Try Alaska if you want to stay in the US, or a Western Carribean cruise.
Depending on whether your family likes animals, I would then suggest San Diego as a backup option. The world famous zoo, and sea world are wonderful. For the adults, there are plenty of things to do there, and nearby beaches.
Based on your children's ages, I suggest Santa Fe, NM for consideration as a great family vacation spot. Many family living rentals are available (spare your sanity and privacy and avoid staying in one hotel room) with homes and condos in or near downtown and the Plaza. You will need a car and can fly into the Albuquerque airport, just about an hour's drive south of Santa Fe. Your children can experience the Native American culture, the great outdoors, and wonderful tastes in this area. Several museums cater to children, such as the Folk Life Museum, and on Museum Hill, Storyteller Joe Hayes spins his wonderful yarns every week. Nearby you will find Los Alamos, if either of your children is a science fan like my son, and Bandalier National Monumnet that is great for hiking and soaking up the culture.
For the whole family, Santa Fe is wonderful for food, art, and meeting people from all over the world. So much more is available. Just let me know if you want to consider more information. Cheers...Marolyn
It may sound either obvious or goofy (no pun intended ) but have you considered doing a combined Disneyworld/Disney Cruise vacation? I did both with some adult colleagues as part of the inauguration of one of the Disney cruise ships a few years ago, and we had a blast! I resolved to take my children on the cruise someday (I took many trips with my family to both Disneyland and Disneyworld growing up and of course children LOVE it.) What's so nice about the park and the cruise these days is they really cater to both children and adults, and they have plenty of services both at the park and onboard the cruises to allow the adults some nice alone time. You can stay at lovely hotels like the Grand Floridian or the Wilderness Lodge to give you a little adult luxury (while still catering to the kids) and then the cruise ships are quite nice as well.
I don't know where you live or what you are looking for, but another great destination for families is San Diego, California. San Diego has beautiful beaches, great dining and shopping and amazing parks and zoos. A wonderful, iconic, family friendly place to stay is the "Del" = the Hotel Del Coronado. It's right on the beach and kids would love it. You must do the Wild Animal Park, where you can take a "safari" through the park's many acres of open parkland where animals can roam around on their own. It's a hit for kids and adults.