I'd have to say my 1972 DeTomaso Pantera. Incredible sexy styling that looks good from any angle, heart stopping performance, a wonderful suspension by Dallara, and a 9 cu.ft. trunk in back. This car not only looks and runs great and does everything well, but it can pack all my wife's luggage (or my golf clubs) for a weekend away!
My E30 BMW was a great car too! Perfect balance of performance, handling and brakes. This was my first BMW and it's clear why these cars have such a following. I just wish I could say the same for my E90 - probably the last BMW I'll ever own.