Indirect turbo diesel cars give lots of economy and miles for little maintenance. Go for a car with a Bosch injection pump that is operated by a throttle cable. Fly by wire is not so hot on these cars.
Cars I'd recommend:
BMW e36- one of the six cylinder cars, Change the oil regularly and that will be all you need to do for 200,000
BMW e30- older still, the 318is is a modern chain engine and zingy and peppy. The 325i is nice, but cylinder heads do crack. I still have one.
Pug 306 td. EVERYTHING goes wrong except the engine, which is loved in Africa and can be converted easily to run on cooking oil. I have one of these as a daily slogger, awful, but cheap.
Mk2 Golfs, as said above, well built, solid, cheap parts, reliable.
Older cars are more simple, I have an MGBGT (getting a Zetec engine fitted by me) and have recently sold a Capri which I fitted with a 2-litre injection engine from a Granada- the best of both!!! No crappy carbs, reliable yet simple efi... Lovely!