Summer trips there suck. We always go spring or fall when school is in session. It's a MUCH better experience. Family goes there at least once a year.
Also, my parents neighbor owns a private cabin/second home about 15 minutes outside Gatlinburg that he rents out. MUCH better than staying in a hotel or cabin resort where they're all butted up against each other.
As for Pigeon Forge, the shows, shopping, and exhibits are nice. I recommend The Titanic, The Comedy Barn, the outlet malls, and the go karts. They have a couple sweet deals on fast tracks there. My fat 295 pund self was getting sideways.
Just outside Pigeon Forge in Sevierville is the huge friggin' knife store and museum. Love that place.
For food, Bennets is god, Huck Fins is good if you like sea food, Big Daddys pizza is legit. Brick oven baked pizza FTW. Best restaurant for a steak? Great Smoky Mountain Brewery, bar none. Dare you to find a better one.
Gatlinburg is cool too. Park all day for $5 and enjoy tons of shopping, putt putt, and exhibits. Ripleys is great. The Aquarium rocks. Avoid Stars Cars museums if you've ever been. It hasn't changed in 15 years.
Theres tons of restaurants and coffee shops but I won't list all my fav's. Too many. Just walk the strip and you'll find something you like.
As for the national park, as mentioned above, check out Cades Cove, Clingmans Dome, and the plethora of trails and scenery off the side of the road. For a killer day hike take the Alum Cave Bluff Trail to the top of Mt. LeConte. Best views I've ever seen. 5.2 miles long with an elev gain of ~2,600. Stellar. Took me 7 hours at a leisurely pace top to bottom.
I love this place. As others said, if you go during the summer expcet traffic and tons of kids. If you can wait until school starts up it'll be MUCH nicer.
Oh, and I wasn't able to go this year, but DollyWood supposedly has a few more big coasters to make it a bit more exciting.