Kevin:
I think the part that is missing from this discussion is that YOU set up each Customer to receive their Statement in the way that fits them.
For instance, let's say you have the e-mail address for Able Cables. You edit their Customer profile and put a check-mark on the E-mail option but not on Print or Fax. Then you go to XYZ Company and, since you don't know neither their e-mail nor their fax number, you check the Print option but not the E-mail or Fax.
You do this for all of your Customers. As Andrew mentioned, if you have many customers, import the settings for efficiency.
Then when you run each of the Print, Fax and E-mail processes, only the Customers selected for that method will appear.
You will need AR version 8.0 for the e-mail feature to be available.