Jerry Seinfeld was right: "There is no such thing as fun for the whole family."
Traveling with little ones was exhausting, true; but vacationing with teenagers is impossible! Assuming you've even found dates when they are all available at once, finding a suitable place is tough. But we've found it- hiking in the amazing Blue Ridge Mountains. We started when the youngest was 4 years old, and have gone back every year since. It works for even the most electronic of teens (that would be my 15 year old son). Rent a "cabin" (ie: gorgeous wooden house, with technology and hot tubs, reasonably priced when it's not ski season) park on the Blue Ridge Parkway, and hike for free. And if you hit a rock funny and blow out your ankle, 9 rescue workers will carry you back down in a metal basket, and even provide a morphine drip!