For a holiday-specific treat, it would have to be candy canes - with the candy-cane peppermint rather than starlight mint peppermint. Love peppermint, and candy-cane peppermint is the best.
Thanksgiving turkey would be up there, but we have turkey pretty much EVERY holiday. But it's good, though. And my mom has gotten noticeably better and better at making it over the years. Used to, she'd make it too dry, but now, she makes some of the best turkey around.