A corvette that was an anniversary edition - they had a few in the 90s would be worth something some day.
Early 90s Toyota MR2 Turbo - they are fairly rare, they were heavily optioned and quick, but still got good gas mileage. Recently, Car and Driver did a small article on collectible cars from the early 90s and the MR2 made the list along w/ A Mustang 5.0 LX. I owned a 91 MR2 Turbo and wish I still had it. Great car, handled great, good acceleration, bullet-proof, looked like a mini-ferrari. Way, way better then a Fiero, which I also owned.
Early 90s Acura NSX (if you have $35K or so) would be the ultimate option. Exotic car, incredibly dependable, bound to go up in value b/c they didn't sell many.