I think that is an interesting question.
When I think back to the cars I wanted in high school, they are still pretty much what I want now. It makes sense to me to segment them based on price: budget sports cars means an ordinary person could have bought them new, high end cars means you could have bought them used at the right time and the super exotics are never affordable.
So for the pre-oil crisis:
Budget = GTOs, Camaros, Chevelles, some Mustangs and Corvettes
High End = Limited production versions of the above (ie Yenkos, Shelby Mustangs, 63 Z06s, 67L88, 427ci/435hp Vettes)
Super Exotics = Ferrari 250s, Lambo Miura, 73 RS
90s to present:
Budget = ITRs, EVO, Sti ?
High End = SupraTT, NSX, Z06 Vette, Viper, 911s, M5s ?
Super Exotics = 959s, F1, 512TR, F40, F50, CGT, Enzo ?
What do you guys think?