My favorite tracks in general (includes 3 I've never been to) -
1. BRISTOL
2. Texas (location bias)
3. Martinsville
4. Darlington
5. Phoenix
Of the four tracks I've been to, the tracks with the best race experiences:
1. BRISTOL (Amazing atmosphere! Grandstands all the way around; cars crammed into a small venue)
2. Texas (Perhaps a location bias with this one. I've been here at least a dozen times)
3. Charlotte (Very similar to Texas. The great thing about this track: it's close to the HOF and the Hendrick shop)
4. Daytona (fun to attend, but so big it requires a lot of effort to follow cars around the entire length)