As a tourist coming to Nashville, I would recommend the following:
(Not in any particular order)
1. Country Music Hall of Fame
2. Downtown Nashville Historical District
3. Visit Opryland Hotel to see their atrium gardens
4. Visit Music Row
5. Adventure Science Center for the kids
6. Frist Center for the Visual Arts
7. Take a tour bus around Nashville to visit historical sites, homes of stars, etc.
8. Christ Church!