Disney will be the first place we go that will completely 'submerge' us into a place. We've always read up on places and planned things for each day. We really like to incorporate learning experiences with our trips. We really like to try to learn about the area we go to and our kids don't expect "fun" stuff (ie: being entertained constantly) when we go away. That being said, the following are the places we've enjoyed the most in the past couple of years...
We loved Alaska. It was a great education for the kids and there is SOOOOO much to see and do there. We went to Seward and saw the aquatic center and then did a short cruise around Resurrection Bay (whales, sea otters, sea lions, etc). There is an AWESOME restaurant there that serves the BEST crepes there. We also went to the Kenai Peninsula and fished for salmon (awesome experience). Went to Denali National Park (really, if you can, take the train from Anchorage to Denali.....unbelievable views!!!), rode the bus, saw Denali (Mt. McKinley), went to Anchorage and did shopping (on Sundays, there is an Inuit group that does native dances, music, etc.), went to a reindeer farm in the Mat-Su valley and learned about the reindeer and elk (got to feed and pet them both). Hiked on a glacier. Just soooo much to do. We will definitely be going back.
We also love Myrtle Beach, SC. We always rent a house when we go there. It's the Miniature Golf capitol of the world (seriously...over a couple hundred mini golf places!!). Dolly Parton has a pirate dinner theater place there that was really great. We toured some plantations there and also went to Greenbrook Gardens (seriously, an all day place). Of course, lots of beach time and pool time (we rent a house with a pool....always).
Niagara Falls is great. We just took the kids there in August. Kids under 12 don't need a passport to cross into Canada (adults do....check the dept of state's website for exact information on the kids). We showed the kids the St. Lawrence Seaway and how the lock system works. You can look up the times the ships are going through the locks and watch them. Eating at the Skylon Tower at the revolving restaurant was the kids' favorite thing about the entire trip.