Ive been to Jacks BBQ and Puckett's. Pucketts a bit more expensive. Pucketts has alcohol and live bands, jacks far simpler. I really enjoyed them both. I love BBQ and Nashville..ive made the 18hr drive twice! Where did you go when you were there?
I had some excellent BBQ in the virginia beach area also..
As far as "best", once you've had a good amount of bbq; it becomes a matter of taste and what bbq meat/prepearation you are looking for and in what style.
I would assume though in nashville, you're mainly going to get memphis style bbq.
TN has a huge bbq history, enough that it has it's own style; so even an "average" bbq I bet is going to be pretty good.