I second the Pancake Pantry.
If you like music, a great place to go is the Blue Bird Cafe. Its not it downtown Nashville and looks like a little hole in the wall but many singers and songwriters got their start they. They have a website. They often have "songwriters in the round" performances which are awesome. Saw Janice Ian there last year. Its tricky to get reservations to some of the more popular performances though. You need to log on right when they start.
Believe it or not, the Parthenon is a beautiful place to visit, not very expensive and in a pretty park.
A bit of a drive away is the Loveless Cafe which use to be part of an old motel. The rooms of the motel have been turned into shops. They have a website as well.
If you like flowers, Cheekwood Botanical Gardens are beautiful.
And it you want to try something hilarious and a little bit risque at times, there is a tour "The NashTrash" tour this is given in a pink school bus with "make your own hors doeuvers". (Think cheese in a can and ritz crackers). The two ladies who do the tour do improve and engage the participants. and yes, they have a website. They fill up in advance too.
Wild Stallion Saloon often has free line dancing lessons and sometimes have certificates on restaurant.com. Hope that helps. (love love Nashville, cant you tell?)