It depends on my professor, really. There were some of them who were younger and didn't like being called Professor, so their first name was easy to use. Others were older and it was just natural. There was one who insisted you use his "Dr." title... guess he earned it, I suppose.

I agree with Diversion, it really depends who which on of them I'm talking to. I usually just default to calling them sir or miss/madame (depending on what class I'm in) if I have to give them a title. Mostly I don't even have to call them by any name, one of us will just start talking.

Ahaha, too true.

I've never used anything polite, like Mr. or Ms. but then again, in Finland no student is polite enough to use that kind of language. Or wasn't in our school.

Rule 1: Dont look your professor directly in the eyes
Rule 2: Do not speak unless your professor has asked you a question
I haven't talked to my professors enough to really get on a first name basis, but I just say Dr.________

Really it depends on how well I know the person. If they ask that I call them Mr. or Mrs. something, then yes I will. But if I know them really well outside of school and things are much more casual, then it's Dick, Jane, etc.

Take for example: I have a teacher named Lauren Monko. I am not in school anymore, so whenever we see each other I call her Lauren (this is with her permission), but if we're ever in front of her students, it's "Mrs. Monko". See?

Depending on the teacher, I have come to accept that I can call a teacher by their first time. Sometimes I do it when I cant pronounce their last name.

It is wierd to be able to talk so casually with teachers when for 13 years or so I was taught "That's MRS. so-and-so" or "MR. so-and-so"

Well, I don't have any professors, but I have been raised to call elders by Mrs. or Mr. {insert last name}. However, I usually try to mention names when I talk. First of all, they know I'm talking to them and, if not, I can grab their attention somehow.

Usually I just default to "Professor so-and-so", since I don't bother keeping up on who has a doctorate and who doesn't. There's been a stray teacher who insisted on being called by their first name, which felt a bit weird, and my Japanese teacher went by Kubota-sensei, but most teachers seem fine with "Professor".

Hmm. I guess it depends. I'm in a west coast school where everything is pretty informal, and so I assume the default of first name. But coming from Africa it definately felt weird for a while not calling everyone sir or madam and by their last names. But I guess I take a cue from how they address themselves. Some ask specifically for first-name basis, some implicitly by signing off as Jeremy in their e-mails or Dr. Mesa. Failing that, if s/he's a cool, young and friendly person, I assume first names. If they're an old fuddy-duddy (I've wanted to say that for ages!), then it's Pr. Palumbo-Liu or whatever.