I use 7gm of coffee per "cup" (5oz). I believe this is the SCAA (Specialty Coffee Association of America) recommendation. The weight is a little lower (5gm?) if using a french press or other European-made equipment since their coffee "cup" is slightly smaller.
Sometimes I bring out the scale and weigh the beans before grinding but more often I use the scoop that came with my Aeropress. It is pretty good at dosing 14gm of whole beans and is the right amount per unit in the AP. I'll probably go back to the scale whenever I get an espresso machine though.
For volumetric dosing of ground coffee, I believe it's one coffee scoop or 2T per "cup".