I haven't been down to that area in years. You are going at a great time of year, hopefully the fall color will be wonderful.
Lets see, everyone always raves about breakfast at the Burning Bush in Gatlinburg.
There are a couple of quirky places I like just outside of the park:
The Mill restaurant and the Trout Farm, both are out by Townsend TN (near the entrance to Cades Cove). The Trout Farm is fantastic, they give you a pole and you can catch your own or just tell them what size trout you want. Get their blackberry cobbler, its to die for. It near the Tuckaleechee Caverns and springs which is alot of fun to tour.
The Mill restaurant is run by a family out of their farmhouse and you will need reservations but its price fixe and BYOB, its good.
Avoid the chains and seek out the little family run places, also try doing a search at www.chowhound.com
Have a great trip!