Well, this may not be very helpful for someone living in the US, but if you want to know which “pre-2000” car had the best ride here goes–
The older Citroen models with the hydraulic/pneumatic suspension were considered to the absolute best-riding cars on the road–bar none. Anyway, this is a moot point, because that marque has not been sold in the US for several decades and even if you were able to find one in running condition, very few mechanics in this country would want to go anywhere near one of these cars, due to their very odd-ball design.