Funny that you ask this as I've been thinking about vacation destinations that I consider "home run" kind of trips. We spent the last few days in Branson, MO and while it's pretty there...not really my thing. It's OK for a short trip, but it's not the kind of home run feeling I get from a trip to WDW. So, it's made me think about some of our past non-WDW trips and wish list trips to decide what's got the big wow factor.
DH really wants to return to Yellowstone and Grand Teton. We had a great trip to those parks back before we had the kids, and while I don't see us doing the same level of backpacking, staying in the various hotels and cabins within Yellowstone, horseback riding, and guided photography tours should make it a big WOW trip for them too. Hawaii is another of the big WOW trips we're looking at in the next few years- even though we're not big beach people. Also thinking we're going to try and do Boston, NY, Philly & DC and connect them by rail. Alaska and a return to Europe (pref. Paris, Vienna, Innsbruck, Florence, and various spots in the UK) are also on the list- but probably not until the girls are a bit older.