Assuming that we're talking about a job interview with a fairly conservative organization, I'd say straight since it's easier to get straight hair to "behave" and style it in a conservative style.

straight hair?  last year when my hair was still curly from being permed, I put it all up in a bun for my interviews.

I have curly, but very fine hair, meaning I can style it curly or straight without too much difficulty. I've been going back and forth since I was about 13. I would have to say that straight hair is more professional looking. I notice that people that I don't know react to me in different ways depending on how my hair is styled. Everytime I have had to look professional, I have straightened my hair and will likely continue to do so.

Karen: funny! The curls really are the wild side, aren't they?? People just perceive me differently, I think.

Curly. Curly hair always looks clean even if you haven't washed that day. Straight hair tends to look greasy. Like that chick who plays Dr. Jordan on the show Crossing Jordan. When she was on Law & Order her hair was straight and always looked like it was full of grease. Then the first season of CJ it was curly and it always looked freshly washed. When she went back to straight hair it again looked like she had ran bacon grease through her hair.

Since clean hair is more professional looking, I'd go with curly.

I think it depends on the job, if you were going for a job in a department store having either straight or curly would
be fine and perhaps demonstrate fashion awareness. For a job in an office I would wear my hair up, I'm not sure why! Seems to give an impression of 'business person' and practicality.

On The Apprentice (UK) last night all the women had their hair down and straight.

I have curly hair and wear it either in a bun, pony tail, or front up and back for work.

Goody's spin pin is an awesome tool for hair buns small or large.

professorauntie have you looked on the naturallycurly.com website to see if you can locate a good hairdresser? They have a salon finder section with reviews. Maybe you could find someone that way who doesn't charge an arm and a leg for a haircut. 

Oh my. That is indeed sad and unfortunate. Obviously he didn't 'get it' that it takes a long, long while to get hair to grow back after a bad haircut. I hope you have some success soon in finding someone who will cut you hair properly. 

Good Morning America did a little test of curly vs. straight in an interview situation (of course, not a thoroughly vetted study, but interesting to read/watch).

URL: http://abcnews.go.com/GMA/Story?id=5565719&page=2

I interviewed for a super conservative job in a super conservative location (i.e. totally old school, everyone dressed in clothing from the early 1900's--ok, wee exaggeration, but you get the idea) and I went totally curly & wild (my hair was a bit longer and less manageable), but I balanced it w/ a BORING navy pinstriped suit w/ pant legs long enough to hide my 5 inch black platform pumps (I think adding height is good if you can walk in the tall heels without looking like a drunken gosling).  Rocked the interview, got the job, and they met all of my "demands" (wages, benefits, work schedule, etc).

I think you just gotta go w/ the look that is most natural and comfortable for you, so your personality shines (and you are not constantly worrying about appearance while fielding stressful interview questions.)

I will be interviewing candidates for my assistant in a few weeks and my concerns will be much more focused on their attitude, personality, their ability to communicate professionally, if they smile and seem to have a sense of humor, and how well their references speak of them--I could pretty much care less about their appearance unless it's apparent that they haven't bathed in the last decade, or something glaring like showing up in a mini skirt with black lace stockings and bright orange stripper shoes with LED's in the heels...that could be a problem...but, I'm mostly open to creative personal fashion/style.