First old Merc - 1975 W116 280SE. Lovely old car but I bought a dog and it died less than a year later. Very thirsty but petrol was only 50p per litre then.
Second old Merc - 1983 W123 280E. I ended up owning this for nearly 6 years, doing 30,000 miles. Cheap to service. Great everyday driver in London with road presence and enough poke. Bit thirsty but offset by cheap classic insurance at £120 per year. Bits of wheelarch rust but easily sorted. Completely reliable on 2,000 miles long weekends to France and back. Sold on to a friend with 130,000 miles on clock.
Third old Merc - 1992 W124 300E. Only just got this but like it a lot. Less thirsty than W123, lighter, faster and generally more dynamic. No rust on mine and cheap classic insurance again. Only 84,000 on clock so plenty of life left in her yet.
Thanks,
KK