6502's are fun to play with and relatively easy to put together a system with one.
There's still quite a community of us building new systems with the 6502 on the 6502.org forums if anyone is looking for more info re: programming/hardware, hints and tips etc
When I started my goal was to write some simple code, hosted on the arduino, then put together a "real" system with EPROM for ROM and proper RAM chips.
Instead I got distracted porting BASIC, FORTH, and similar things to the working processor. I should get back to it!
I think the Z80 is simpler to get started with than the 6502, when it comes to physical circuits, as it needs fewer components. (Having RAM refresh built-in, for example.)
Do you know if there is a forum for Z80 homebrew systems?
FWIW this is the high-level overview I've put together:
Doesn't get much simpler than that.