Hanson's Block Diagram
See also this article on pagetable.com
The classic and best 6502 block diagram is taken from Donald F. Hanson's paper "A VHDL Conversion Tool for Logic Equations with Embedded D Latches" (http://www.ncsu.edu/wcae/WCAE1/hanson.pdf), which was presumably presented at Workshops on Computer Architecture Education at HPCA 1, January 1995
"A block diagram for the 6502 microprocessor is shown in Figure 3. This was drawn to correspond to the blueprint."
Cleaned up version copyrighted 2011 on the author's website. "This is the result of work done in 1982 from the blueprint of the 6502 microprocessor"