Difficult to say.
On one hand, i've always had something for the Porsche 911. An early one, pre 1980, would be a good dream car.
On the other, the Honda NSX captivates me since its introduction in 1991... similar to the Ferrari 348/F355 in performance, for a fraction of the cost, and reliability the Italian donkey could only wish for.
But then again, i've always loved the Jaguar XJ220, and the Bugatti EB110... Plus there are the Group B/Rally homologation specials, like the Audi Sport Quattro, the Lancia Delta and the Stratos, the Escort RS Cosworth and the RS200, the Peugeot 205 T16...