Well, it's been rather a while since I was at university, but all of my professors introduced themselves at the beginning of a course, A few discussed their experience, but were pretty brief about it.
Sometimes, they said things like, "You'll find me serious about the subject, impatient with those who don't apply themselves, death on those who come to class unprepared, but I do enjoy the light touch when appropriate". That "speech" was from one of my profs. I found it extremely helpful, as it gave me some insight into what to expect of him. I learned more from that prof than from any of the others. Others who spoke of themselves and/or their personality were more brief.
Personally, I think such intros are important, for both the prof and the student. I felt almost that we were on a trip together through unfamiliar territory, when they revealed something of themselves. If they were not so inclined, it felt more as if they were just shoveling information at me! I think it's more conducive to learning when a student feels comfortable with his teacher, and intros are a good way to establish that.