Hey man, sorry I'm just now seeing this. I've been MIA for a little bit while on the Vol football boards.
I'd say the place you are talking about is Fat Mo's. I've never eaten there, but I'd like to sometime. Its kinda like a fast-food place from what I can tell. Its in the old Burger King building. If I want a burger in that area, I usually go to Fudruckers a few miles down the road in Governer's Square. They're a chain, but they're very good.
I know this is a matter of opinion, but you won't find a better burger in the world than at Litton's. Litton's is less than a mile from my house and I eat there all the time. It is a family-owned restaraunt that started out as a meat market over 50 years ago. Anybody that comes to visit me in K-town goes there first. Its an awesome place with very reasonable prices for sit-down service. Any burger on the menu will be incredible and very filling! Desserts are also awesome, but you'll have to get one to go because you won't have room left in your gut. It is located on North Broadway on the North side of Knoxville. The area is commonly referred to as Fountain City. Get on Henley Street downtown (where the Convention Center is) and head straight out. Henley becomes Broadway and you can't miss Litton's on the right. If you're comming from Pigeon Forge, take the 640 bypass off of 40 West. Then exit 6 is Broadway. Turn right and you'll see it on the right about 2 1/2 miles up.
The Cumberland Grill is the name of the upstairs portion of the Copper Cellar. It is more casual and a little cheaper than downstairs. It is owned by the Connor Corporation which also owns Calhoun's, Chesapeakes, Cappaccino's, The Chop House, and Connor's. There is a Connor's and Chop House in the Five Oaks outlet in Pigeon Forge. All are great! On Sunday after 4, you can't take advantage of the "burger deal". Any burger on the menu with fries is only $3.99! They are great burgers and a steal at that price! I usually go for that once a week.
Prepare for crowds and traffic big time in Sevierville/Pigeon Forge on Friday. That is thier biggest shopping day of the year so be prepared to spend a good portion of the day.
Good luck finding parking for the game!

I'm an usher, and we don't even get parking.