People in ad schools, more often than not, don't understand the difference between being a designer and art director. It is huge, and this is a pretty good problem. There are even some people working who aren't quite sure what the difference is. George Lois sheds some light on this at his offset talk. Hegarty talked about it a bit in his book.
But if you're still confused I came across an illuminating piece the other day. Not all you picture folks are big readers but you should try to choke this down. It'll help you realize if you are (or want to be) an art director. (and if you aren't already reading Ad Teachings you should add it to your blogroll)
Ad Teachings - Can, or should, a graphic designer become an advertising art director?