1. Renault 4 (1961-1992)
THE EXPERT: Adrian van Hooydonk
Head of design, BMW Group
THE ENDORSEMENT: "I used to own one. It's a fairly boxy thing, but I appreciated it for that."
THE BACKSTORY: Introduced in 1961, the 4L, as it's also known, embodied the kind of versatility taken for granted by RAV4 and Escape drivers as one of the first economical, durable hatchbacks.
THE COST: They're rarely seen in North America, but excellent European examples range from $3,000 to $5,000—expect to pay an equal amount in shipping, however. Also make sure you're getting the left-hand-drive French "La Quatrelle" version, not a U.K. model.
2. Buick Riviera (1965)
THE EXPERT: Ian Callum
Design director, Jaguar
THE ENDORSEMENT: "It was a very beautiful, very singular design. One of [GM styling icon] Bill Mitchell's best. There was something almost Italian about it."
THE BACKSTORY: Known simply as The Riv by cultists, this model represents the car's high-water mark for design—it came with distinctive clamshell headlamp covers and cleaner body lines.
THE COST: It's $18,000 for a model in decent shape, with the top-line Gran Sports commanding more than $50,000 at recent auctions.
3. BMW 3.0 CSL (1972-1975)
THE EXPERT: Martin Davis
Design manager, General Motors
THE ENDORSEMENT: "It has great structure and proportion. It feels like the car's body hangs off that distinctive tapered shape, which is masterfully executed."
THE BACKSTORY: The CSL was based on the already trim, elegant CS and is regarded by many collectors as the most beautiful Beemer of all time. Mid-century American modernist Alexander Calder lent his aura to the brand, putting his brush to a CSL race car in 1975.
THE COST: A prime 1973 street model recently went for $70,000.
4. Alfa Romeo 33 Stradale (1967)
THE EXPERT: Filippo Perini
Design director, Lamborghini
THE ENDORSEMENT: "It was a car that was never quite celebrated. Designed by Franco Scaglione, it remains for me one of the most beautiful sports cars ever."
THE BACKSTORY: The most expensive car in the world when it debuted in 1967, this 230-horsepower beast weighed just 1,500 pounds. Despite a bold design, the exorbitant cost doomed it to commercial failure, and fewer than 20 were made.
THE COST: A fortune—if you can find it. A prime 33 Stradale will fetch well more than $3 million at auction.
5. Smart Fortwo (1998-2013)
THE EXPERT: Max Wolff
Design director, Lincoln
THE ENDORSEMENT: "Its industrial-design aesthetic was an attempt to redefine the small car."
THE BACKSTORY: Designed by Mercedes-Benz parent Daimler with input from watchmaker Swatch, this tiny two-seater is known for its interchangeable, boldly colored body panels.
THE COST: Little-changed since the car's debut in 1998; a new model will cost you around $13,000.