I posted this in another thread, but here's my take on what PD should have done with the NASCAR license.
Now, it seems as if PD isn't going to implement NASCAR fully into GT5, with just some of the cars and only a few tracks. But, if PD wanted to follow that idea, but give more than just a couple tracks, here's what they should put in, in my opinion.
1) Daytona (already confirmed)
2) Indy (already confirmed)
3) Infineon (not confirmed, but likely will be in anyways)
4) Texas (Kaz & Co. visited there, 1.5 tri-oval, night/day racing in real life)
5) Bristol (most famous short track, day or night racing, very unique)
6) Richmond (a short back, but bigger than Bristol, it's a unique tri-oval design, day/night racing)
7) Phoenix (a mid-sized track with day/night racing, very unique tri-oval design in a unique location. Cool desert views for a NASCAR track)
It would keep the track list relatively short, and they almost all would fit in nicely with the day and night racing PD has implemented for GT5. Also, it ensures no two NASCAR tracks are alike as they bring their own unique characteristics. It gives a sample of all the different types of NASCAR races. Places like Charlotte, Talladega, and Atlanta are all really cool tracks too, but Charlotte and Atlanta are VERY similar to Texas and Talladega is similar to Daytona. Darlington would be another great choice, but doesn't really fit in for GT5, maybe a future GT game with more NASCAR content.
Also, a lot of NASCAR tracks have road courses to go along with their oval tracks, making the location an even bigger plus.