I'm going to my parents for Thanksgiving this year, so aside from a few ornamental gourds and pumpkins I haven't done much Thanksgiving decorating. But if I was hosting this year I'd definitely being making some of these ideas my own...
For a more modern spin on a harvest theme, paint some leftover Halloween pumpkins white and use them on your Thanksgiving table.
Use some autumn colored leaves in place of these green ones if in your climate they're no longer green. You could also try pine branches or just interesting bare branches.
We're used to seeing a lot of dark and earthy tones in Thanksgiving decor, but I actually like these fresh, light spaces. See the little pumpkins hanging from natural-fiber rope in the back?