It's really all about taste, and in my case, what is not normally seen on the street.
Also, I wouldn't be a good collector as I don't see the value in buying a car and not using it.
Personally, I like one-off and strange models, to name four:
The Renault R5 Turbo II
The Ford Mustang SVO
The 1st gen Acura Integra Type R
The 1st gen Volkswagen GTi - either American or Euro
I've never been as much a Lotus Elan fan. I like the early to mid-60s Cortina much more.
And speaking of Lotus, I doubt the current Elise will ever gain the prestige of old Lotus cars from the 60s and 70s. Not with a Toyota engine...
With that said, I also wouldn't mind a Ferrari 288 GTO.