Did you already find
Akuma's ergonomics thread (with links to others)?
This PDF has a great image for monitor height and angle. In case the link gets broken, the details I thought were interesting were:
1. the top of the screen about an inch below eye level
2. the screen is around 12°- 18° from vertical.
More pepper for this pot:
My joystick bases are a few inches below my elbow height, which is fairly comfortable.
My monitor shelf angle is adjustable from ~15° to fully horizontal. The full vertical screen position was for watching shows from the couch, but I never do that so it is always at ~15°. Angle adjustment is a fairly easy feature to implement, though.
My monitor is about 6 inches below eye-level. This gives me a tendency to lower my overall height during intense Robotron sessions by standing with my feet further apart. This stance puts me close to eye level with the top of the screen. (I didn't really think about this stuff so technically when I built my cabinet)
It is good advice to play sessions of your most often played games at various heights to really determine what is most comfortable for your Player(s.)