I don't have any specific recommendations for resorts, but some general bits of info and cautionary notes. Christmas break is going to be WAY busy at all resorts and prices sky high. Also, be aware that flights are going to be full and usually over booked, which can make for some stressful flying. Before you get your heart set on a particular country or destination, suggest you check out the air connections. If you can get a non-stop somewhere, I personally would put that destination at or near the top of my list. I have friends who booked a family getaway (with adult family members, flying from different places) at Christmas one year. Several of them missed a connection due to bad weather. They ended up losing two whole days of their vacation because, once they missed their original connection, they literally couldn't find any flights with open seats to get them there. It wasn't a matter of the airlines not trying to help them get there, but there literally were not any open seats for days..

As far as particular resorts, we don't have any kids, so can't really help much with that. I assume your kids have passports?? If not, get them. Your main options are going to be Mexico (mostly Cancun), Jamaica and the DR. With Jamaica and the DR, recognize that the hotel could be a long way from the airport, which you may not want to deal with, with three small kids. Most vacation flights for JA fly into MoBay, so if you're looking at JA, look for someplace that's not real far from MoBay. For the DR, be advised that there are about 3 major airports there, so check air routes from your area. Hope that helps a little bit.