I appreciate the E28, but I don't think the M5 is the most suitable version of it, and it's the same thing with E34.
Between E39 and E60 it's a close call, but I prefer the elder since it's not such a techno-fest compared to the younger.
But now seriously, I'm between the E39 and the E60. But I'll take the E60, it was just so ahead of his competitors when it was released that even today they are comparing it against its new rivals and it is still better in some aspects.
E34 all the way. It was the last of the hand built M cars. The E28 E30 and E34 were all shipped to M division headquarters as bodys in white and assembled by hand then sold. the E39 was made on a assembly line in one of BMWs big ass plants
EDIT: yes you could argue that the First Gen M coupe was the last hand built car but it was still made in a normal BMW plant instead of at M Division