If you want to try a couple of things that are different, here are two that I recommend.
The Mirage Knoxville / Cairo Cafe on Gay Street.
it's a Mediterranean restaurant & lounge where you can either sit American style tables, or Middle Eastern style on pillows and knee high tables. This one is really just for the loads of atmosphere. If you're a "Steak and Potatoes" eater, you may not love the menu. There are a few Entres, but a LOT of appetizers, mostly different dips served with warm Pita Bread. After 9 or 10pm, it goes 21+ (because of the indoor smoking laws) and you can order a hookah for your table.
The best way to enjoy this is to have a few friends go with you (like 8 people total) and order all the different appetizers and hang out, smoke the Hookah (which is farily cheap, I thought, at $10 a bowl which will last your table the better part of an hour). There are apparently Belly Dancers there on certain nights, but I've never been there at the right time.
The Melting Pot on North Central.
This one's a chain, but I was really impressed, especially for it to be hippy food! :P Each table has its own Fondue warmer, and the meals are kind of "package" deals. There are a few variations of what entre meats you get, but each meal comes with an appetizer, main course and desert. Most of the items are made for 2, so it's a nice place to take a date. I consider it a little pricey, it cost about $100 including drinks, but I left really full. Apparently they have a nice Wine selection, but there are no beers on tap! Luckily they do have a few brands in bottles.
For more normal stuff:
Wild Wing Cafe on Campbell Station Road. Another Chain, but I think it's the only one in TN. Tons of good wings to choose from, 20 beers on tap (expensive beer, though).
Smokey Mountain Brewery in Turkey Creek. As you could guess, the beer is more impressive than the food, which is a tad pricey.
I'm closer to Oak Ridge than Knoxville, and I love Mexican, so I have to mention El Areiro's on the Oak Ridge Turnpike. It is the best authentic mexican I've had, the prices are cheap, and the staff is friendly.