i want something that can last me for many years
What people fail to realise is that cars built over the past 15 years or so just do not last like old cars do. No car you buy now will still run well or look good in 20-25 years.
As a Brit, I don't really understand the US obsession with Jap cars - I know it's all down to individual taste but a Honda Civic for example looks boring to me.
You want something interesting, something that sets you apart from the crowd of boring Jap and American cars. Always buy German when you can afford it - and at $20000 you can definitely afford it.
What you haven't taken into account is that as well as running costs, you have the depreciation costs of a car. Something like a Civic or a Mazda is going to be worth absolutely nothing in 10 years. That's possibly $20000 down the toilet.
Absolutely
nothing in the world beats an 80s/90s era Mercedes-Benz. I suppose that they are probably rarer in the US but over here in Europe there is a reason why you see them everywhere, they last... and last... and last. They require little maintenance and servicing is extremely cheap as there are no fancy computers which can go wrong like on new cars.
My friend has just bought a 1990 Mercedes 190E which has 208,000 miles on the clock. It literally looks as though it's come straight out the factory (and bear in mind that this has been on wet, salted British roads all its life which in 99% of other cars would cause major rust). My family also has a 190E 2.5-16v and a 280TE station wagon with 155,000 miles and 180,000 miles on the clocks respectively. They still drive like they're new.
Depending on the size of car you would like, I'd recommend a Mercedes 190E (compact saloon) or a Mercedes W124 300E (saloon). If you want a racier look, you could go for a Mercedes 190E 2.3-16v or the 2.5-16v (a later variant) which were the competitors to the BMW M3 at the time and have around 200bhp.
In very good condition and low mileage (anything up to around 170,000 would be acceptable) you could expect one of these to last you as an every day car for at least another 15 years. They are also very cheap so you don't have to spend all of your money and will also certainly go up in value.