Even though I never owned one, the '020 surely was a milestone.
But I like the '030 best since it was the most advanced CPU on any Amiga main board - and because it really kicked ass when it came out, architecture and speed wise. The '040 had its match in the i486 and the '060 could not really beat Pentium Classic performance. :-(
Plz don't flame me, I love 68ks, esp. for Assembler programming.