I believe most of mine have already been nominated, but here goes.
The BMW 8-series. An older guy who lives near me drives a black one occasionally, and I can't help but gawk every time I see it. It seems worth buying on the basis of looks alone.
The 2nd generation Ford Probe. Aside from the questionable choice of name, the car seemed brilliant. It looked great, and drove very well. The 2.5L DOHC V6 sounded fantastic, and used some fairly advanced technology, but was drastically overcomplicated and had terrible reliability, coupled with a weak transmission and clutch. Had the car had the power it needed to compete with its contemporary rivals, and halfway decent reliability, it might have made more of a name for itself. Of course, there was the problem of Ford's FWD V6 powered coupe being better than it's V8 powered RWD muscle car...