The 68000 is, to me, the undisputed King of pretty assembler. It had a wonderfully orthogonal instruction set. It appeared to be a super set of the PDP-11.
I found the IBM System 34,36,38 line ok to use as a development platform for COBOL applications as kind of vanilla systems. My last 5 years in IT the IBM RISC 6000 UNIX systems I worked with ran circles around IBM's old flagships.