We travel quite a bit. We were unable to have kids for several years, so we distracted ourselves by throwing our disposable income (what was that, LOL?) on vacations. Then, after 15 years of trying, we had a little boy. Since we were almost 40 and used to our vagabond ways, we just packed him a bag and took him along. So far he's been to Cancun, the Grand Canyon, central Oregon (snowboarding), northern Washington and the Canadian border (family reunion, hiking), several trips and several resorts in the Phoenix area (family nearby), Austin, Dallas and San Antonio (we live in bordering Oklahoma), we did Disney last May, we're doing Disney and Universal this Christmas, Washington DC next spring, and Macchu Picchu next summer. None of these trips have been more than $4k (Macchu Picchu comes the closest) but there's only 3 of us and we look for deals. Great places for a family with kids, especially if you're coming from the Midwest:
Austin -- fantastic funky fun city, that whole thing with the bats flying at sunset has to be seen to be believed (only in the spring, I believe?)
The Grand Canyon -- it's iconic, the Brady Bunch did it for a reason. Majestic and amazing photo op. Tons of things to do in the area.
San Antonio -- The Riverwalk, Sea World, La Fiesta (if you go in the spring) with tons of food and music...it makes its own fun.
Central Oregon -- Mt Hood (skiing, snowboarding, all kinds of snow stuff), The Sisters, Newberry National Volcanic Monument
New York City -- Central Park Zoo, Tea at the Plaza, FAO Schwartz, children's theatre, Museum of Natural History...we've haven't taken our son here yet, we're waiting until he's 9 or so. Upstate New York for scenery.
We're not beach people (we went to Cancun because my husband is a Modern Languages prof and he wanted to see Chichen Itza) so I can't help with anything beachy, and I don't do water so I have no cruise info. Hope that helps...I feel like it's a lot of Texas, haha.