Z80 machines w/ CP/M and the IMSAI 8080. I like the old IMSAI 8080 machines and got to use one many years ago and it’s fun and visceral to program with machine code. direct understanding.
I even wrote a simple text-based adventure game for it, first in C, then in z80 assembly.
I grew up with the ZX Spectrum, so the Z80 is a processor I remember fondly.