Gatlinburg is one of my very favorite places to go. I LOVE the mountains and even if the Smokies aren't as towering as the Rockies, they are still beautiful. What you want to do really depends on the description of the group going
Kids? Pigeon Forge and Gatlinburg are both filled with kid-magnet attractions like mini golf, go-karts, and Ripley's museum. Year around ice skating in Ober Gatlinburg is fun, too.
Daredevils? Try the indoor skydiving in PF or one of the Bungee Jumps on the strip, or they can slide down the mountain on a sled at Ober Gatlinburg.
Nature lovers? Oh, hike in the park!!! There are many hiking trails, varying from 1/2 hour/handicap accessible to several days/strenous.
Theme parks? (Duh!) Dollywood is grand, but do be kind and let it stand on its own laurels rather than comparing it to the ones in Orlando. There is also a new waterpark next to Dollywood. I know someone trying to sell 3 tickets if you're interested...
Restaurants? Some excellent ones. Some locals, some chains.
Shopping? PF is a shopper's mecca with, I think, 4 major (read --LARGE!---) outlet mall complexes.
Crafts? What Gatlinburg was built on. Appalachain ingenuity.
History? You must go through the one-way loop that is Cades Cove. The valley is preserved just the way it was when the park was formed. There are homesteads from each stage of it's development from the early 1800's up through about 1930 or so. Cemetaries, cabins, churches, plus more. If you luck up schedule wise you'll get to see them making sorghum. YUM!!! Watch for deer, black bears, and other wildlife.
Want to see several states at once? Walk up to the top of Clingman's Dome, the highest point in TN (2nd highest east of the Mississippi) It's a surprisingly easy walk considering it's such a high mtn.
Sweet tooth? The taffy and fudge factories in Gatlinburg will take care of that.
Like to look at fish? There is a super nice aquarium in Gatlinburg you won't want to miss.
Like to catch fish? Many mountain streams to fish for trout.
Like to eat fish? See "restaurants" above.
If your trip is long enough, there are caves to explore, white waters to raft, mountains to climb, shows to watch (Pigeon Forge is beginning to look like it's trying to challenge Branson in that venue), and many grand adventures to capture on film. One MUST DO photo is the "Welcome to Gatlinburg" sign--you have to have someone stand in front of it and get their picture. Once it's done, it becomes a family tradition that will go on for years.
BTW, I've only scratched the surface here. Now that you've got me on the subject I'll probably be thinking of things to add for days!!

tmo