I would say Gatlinburg/ Pigorn Forge.
2nd that. Went 3 years ago and had a great time, and it was relatively inexpensive for a week. Dollywood is very nice, and plenty of other things to do in the area including the massive state park, the Ripley Aquarium (a don't miss from someone who doesn't like zoo's and whatnot), and plenty of shopping and other stuff. Don't know what your budget is, but getting a cabin in the mountains is very cool. I think if you get it through
Dollywood's travel page, you get free tickets and some other perks for the park also. There are a ton of cabin services in that area, so be sure to comparative shop if you decide to go that route. Cabins are usually 10-15 minutes off the main drag.
We didn't book through Dollywood last time, because I didn't know about the perks or their rental service. I think the place we used was about $1100 for 6 nights. It was up in the mountains with a great view, 2 bedroom, pool table, kitchen, etc. Definitely was worth it IMO.
If you go, make sure to hit the
Wild Plum Tea Room for lunch. It is a little off the beaten path, but is well worth the time to find it. When we were there they only served lunch, and it filled up fast, so we got there 15 minutes or so before they opened. Great food, and ambiance, and this was the meal we remember the most from the trip. The TripAdvisor review can be found
HERE.
The whole family enjoyed our time in the Pigeon Forge/Gatlinburg area so much, we are planning to go back for Christmas next year, because Christmas is a big deal down there.
Good luck with your planning wherever you decide to go! Tennessee is a great state with a lot of options.