I've thought about Montreal but not for February... though the sugar shack thing has me intrigued. Though I must admit, the logic of Mexico/Central America (not too gougerrific airfare + food the kids will actually eat) is hard to beat at the moment; much as I love the idea of somewhere in Asia, I fear them (well, one of them) whining about food for two weeks.
Basically, anywhere I could drive to, I would, with 4 of us. So airfare is probably not an issue for Montreal, though in reality, it's tough to find anywhere that airfares aren't upwards of $500, except maybe puddlejumpers to Two Forks.
Thanks again, all, for your suggestions and experiences...