Wandering through the internet ether the other day, I found a couple of useful "how to" pieces for students. Both are written by Michael Leddy, who blogs at Orange Crate Art, a site well worth a visit.
The first is "How to Email a Professor." The second is "How to Talk to a Professor."
Anyway, I thought these might be useful.
And seriously, if you're a student, take pity on your professor who probably has 70-100+ students each term, and when you appear in the office door, unless you're SURE your professor will instantly recognize you (because s/he has called you by name on numerous occasions), introduce yourself and give a context for your visit.
Oh, and book buyers, just don't come to my office, please! I give my books to a local organization that sorts them into "useful overseas" and "sell to fund mailing more useful overseas books overseas" and then either sends or sells them.