@ Harlequin
Most cultures have had a Midwinter Festival of some kind, and the correspondences are mostly constant across the board. The same can be said of Samhain and the others, yup.
However, and this is the point i'm, in a very civil way, trying to get to, don't you think it may come as, maybe and just maybe, slightly pretentious to refer to the festivals by their old names when we aren't holding the festivals in the way those names meant? One way or another, no matter how serious we are about holding them, we lack the proper context, cultural and social, to see in them the same meanings and the same powers. So why not just call them, say, x-mass, haloween, and the rest? Their modern names are as devoid of meaning, for us, as the old ones, but at least the modern ones don't come as, uhm, attention not-whoring-but-almost?
In the end the modern names still mark a date, and we aren't insulting those who hold the old names and their true, deep meanings dear by appropriating those for our own use.
Gee, it's really hard to speak the Watch tongue.