I'm probably Stockholm Syndrommed about 6502.  It's what I grew up on, and I still like it a great deal.  Admittedly register-starved (well, unless you consider the zero page a whole page of registers), but...simple, easy to fit in your head, kinda wonderful.

I'd love a 64-bit 6502-alike (but I'd probably give it more than three registers).  I mean given how little silicon (or how few FPGA gates) a reasonable version of that would take, might as well include 65C02 and 65816 cores in there too with some sort of mode-switching instruction.  Wouldn't a 6502ish with 64-bit wordsize and a 64-bit address bus be fun?  Throw in an onboard MMU and FPU too, I suppose, and then you could have a real system on it.