cut-and-paste from my comment on a later thread:
One should always refer to Doctor Jill as Doctor of Education Jill - apparently she takes her title very, very seriously, and as such we should give her the courtesy of using that title in its fullest, most accurate sense. Also everyone knows that when it comes to academic degrees, one is hard-pressed to find anything more useful and more valuable than a doctorate in education.
Lotsa info on her at wiki.
I doubt many folks with the same degree use the title Dr..