1989 Thunderbird Super Coupe. Over 225,000 miles (very hard miles) and other than some moderate mods to the engine to enhance performance (custom bent headers, roller cam, slightly smaller super charger pully, chip and exaust) the only significant down time was to replace the clutch at 135,000 miles. Damn near bullet proof.
My current car (Audi S4) has been rather trouble free for it's first 15,000 miles of life. Keeping my fingers crossed.