The Liberty is one of my favorite restaurants in Charlotte because not only are the burgers terrific, but anything you order is quite delicious. The service is always good and the ambience is lovely. It's a very laid back atmosphere with perfectly lit dining rooms and bar. I bring friends here frequently because it's not so noisy that you can't have a conversation (unless you're in the bar during a crazy game; they do have tvs in the bar area).
I highly recommend the Crunch Burger and the sublime homemade macaroni and cheese! Oh and did I mention they have a great selection of beers?