Recently stayed at the Gaylord Texan. Enjoyed it very much. You may remember my comments on my blog post (Back on those Texas Plains). Ended up with a huge suite overlooking the atrim. No complaints here.
Everything I've read about the Christmas display at each of the properties has been great. It would be fun to see sometime.
In general, I'd say that once you check-in at a Gaylord property, you don't really feel like leaving right away and with so much to explore, you don't really need to. The Texan felt sort of like an indoor Disneyland if Disneyland were entirely Texas themed. I didn't really look into activities as I only stayed the one night, so I can't really help there. The place did not feel crowded at all over Columbus Day, but I imagine Christmas might be a different story. I'm pretty sure you would not be disappointed with a stay at any Gaylord location.
Gaylord Opryland is great anytime of the year, but it is truly special @ Christmas. The atriums, the lights and decorations are stunning. There are always great music events, shows and, of course, Santa, the splendid ice rink, ice tubing. We were there two years ago with a family group of 15. Even with a wide spread of interests and ages, everyone was entertained and there were plenty of options for visiting in smaller groups.
The place is huge and can be intimidating, but we never felt crowded or rushed. Oozed with the best kind of Southern Charm.