1. Everyday, low-cost cars offer so much: Fast performance, high gas mileage, unheard-of safety features and so many luxury touches - power windows, door locks and side mirrors, cruise control, auto-dimming mirrors, power disc brakes, lumbar adjustment, killer audio system, heated rear window defroster, keyless entry system, alloy wheels, etc. I think that the variety of audio options available in today's cars would astound people. (Most '65 cars didn't even have FM radios.) So would the quality of sound. And the features available because of the use onboard computers. And navigational systems.
2. Ordinary 2005 sedans will run circles around most 1965 sports cars. On the straightaway and in the curves. And get decidedly better gas mileage.
3. The rise of Japanese brands - virtually unknown outside of California in 1965.
4. The disappearance of household names like Plymouth and Oldsmobile. (I don't think that the average 1965 man on the street would be surprised that Studebaker, Imperial and American Motors are gone.)
5. The great variety of luxury brands and models available. Forty years ago, a large Mercedes sedan, like the 250 SE, was the size of a Rambler. The biggest BMW offered - the 2000 - had a wheelbase of only 100 inches. Hardly a luxury car by American standards. And ... what the hell is a Lexus?! Or Infiniti? Or Acura?
6. Overall quality and serviceability of today's vehicles would wow people of 40 years ago. The worst cars of 2005 are better than the finest cars of 1965 in terms of fit, finish and reliability. You rarely see relatively-new cars broken down on the side of the road - a not-uncommon sight forty years ago. People would be astonished by the very concept of 100,000 miles between tune-ups. (A 1963 VW Beetle required an oil change every 1,500 miles and valve adjustment every 3,000 miles.)
7. The preponderance of truck-like vehicles on the roads of 2005. At the 1965 New York Auto Show, General Motors didn't bother to exhibit the Chevy Suburban or its two-door variant. Chevrolet - a single marque - now offers the Avalanche, Blazer, Equinox, HHR, Silverado, Suburban, Tahoe, Trailblazer, Uplander, Venture and God knows what else.
8. That most cars didn't really get bigger in 40 years. The 2005 Corvette is very close to the overall size and curb weight of the 1965 Sting Ray. The 2005 Lincoln Town Car is five inches shorter than the 1965 Lincoln. But truly lightweight small cars are gone. The new Beetle weighs 1,100 pounds more than the air-cooled one of forty years ago. The '65 MG Midget weighed less than 1,600 pounds; the MGB was 1,920 pounds. The 2005 Mazda Miata weighs 2,447 pounds.
9. Safety features - can you even imagine doing a 40 mph offset barrier crash in a '65 Mercury Comet? The widespread availability of ABS braking systems, traction control, directional stability control, multiple air bags, etc. would be incomprehensible to most people back in 1965.
10. Buying cars using a household, smaller-than-a-briefcase computer hooked to a coaxial cable. Or to "airwaves". Now that's amazing!