In our parish, we have a pastor, who is addressed as "Father First name." (Those whose official function we used to refer to as "curates" are now generally called assistant pastors; they, too, are addressed formally as "Father First Name,") In social situations, however, when a pastor or assistant pastor is a close friend, most are quite comfortable with being addressed by their given names. On an envelope, one would write, "Rev. Fr. John Smith", as he is an ordained priest.
We have three married deacons in our parish. Although one could properly be said to perform the administrative duties of an assistant pastor, they are individually addressed as "Deacon First Name." (Again, socially, or in informal meetings, good friends or coworkers generally address them by their given names.) A more formal letter to a deacon would be addressed to "Rev. Mr. So and So," as he is an ordained deacons, not an ordained priest.
Heads of various ministries are, depending on their credentials, referred to as Youth Minister, etc. when they have a degree in pastoral ministry, for example, or as "Director of Social Ministry," "Director of Religious Education," etc. -- obviously, more of a job description than form of address -- but, in most Catholic parishes these days, directors of individual parish ministries are addressed by their first names or honorifics (such as Sister Mary, Brother John, Mr. Smith), depending not only on their personal preferences but also on who is doing the addressing.
As you mentioned, customs can vary from place to placehowever One Monday morning shortly after we moved to Georgia, I mentioned to a Baptist coworker about something "the pastor of my church said yesterday in his homily."
My young coworker looked surprised. He said to me, "I didn't know Catholics had pastors; I thought they only had priests."
I explained to him that a calling (to the ministry, priesthood, rabbinate, etc.) is a vocation. Terms such as "pastor" really designate a role within a broader calling. Thus, Catholics (and members of many other Christians denoms) don't address pastors as "Pastor So-And-So," although that is the job description of many priests and ministers. But in many Christian denoms, to address them as "Pastor X" would be akin to calling one's different physicians "Surgeon Smith," "Pediatrician Potter," and "Gynecologist Jones," instead of "Dr. So-and-So."
