Been looking at E36's, E32's, and E34's. Opinions?
*Also to a less serious extent the old 6 series coupes.
E36's are not worth your time. Too complicated, not the best built and will break expensively.
E32's, well, ask Spectre about his opinion.
Suffice to say, it's the same story as the E36, but worse.
E34's are a good choice. Solid 5er, but some of the engines may have VANOS, IIRC, which will be expensive to service/fix. The VANOS can fail, with symptoms showing at any where from 90-100k (usually due to poor maintenance and/or abuse).
E24's while pretty, are also not a good choice. Limited parts availability, expensive to service.
Also, if you decide to get any car, do not cut out the speaker holes to expand them, it will ruin the originality and look of the interior.