semi-homemade micro

All the talk about building a mini from TTL got me thinking about homebuild micros, and what one would look like if I decided to build one (been playing with my IMSAI, too, which probably accounts for some of it) RISC would be out, due to difficulty of assembly coding, and 8086 seems a bit dull. Z-8000, TMS9900, and RCA1802 seem unavailable, and 6120 doesn't have many registers. Looks like the best available ideas from an ease-of building and obtaining would be Z-80 (or variant), 6809, or 68000 (close to top in complexity, esp. if a front panel is wanted). 6502 could also be a possiblity. I suppose either native IDE or another system serving as a storage server would be the way to go, the IDE could either connect to a old drive or a smallish CF card, and flash firmware would probably be best, or EEPROM. SRAM seems to be the way to go for smaller systems. Just wondering what the thoughts of the list would be for specs of a "new" hobbyest micro.