I have an interview with a new company on thursday, what kind of questions should I ask, other than the standard ones about health, dental, salary. I know those are the questions you should ask last.

Try to take an actual interest in the job that you are applying for. Ask what a typical day's activities you would be working on, or a typical project.

If you are replacing someone, ask what their greatest asset to the company was and, what did they need to work on to help the company. What objectives do you have for my position. What are the most pressing concerns for my position in the coming months.

Wouldn't hurt to do your background on the company too... "I read that you purchased company XYZ or landed XYZ contract.. how does the future of that affect my position..."

Until you get a job offer. I wouldn't even bring up benefits or salary yourself.

Don't be shy about asking questions about the company - this is your opportunity to really get a good grasp on what it would be like to work there. Find out as much as you can about how your job would work. Things I'd ask are:

Who will I report to?
What's the org chart look like?
What kind of review process is used by the company?
How do promotions and raises work?
What are the details of my job?

Also, if you are given the chance to talk with other employees during the interview process, ask them how they like the company and what their experience has been like.

Discussions about salary and benefits should probably wait until they've made you an offer - that's the best time to discuss terms. The interview process is all about them getting to know you better and you getting to know them better, to see if the job itself is a good fit. If they make you an offer, that's when you discuss and negotiate compensation.

Wouldn't hurt to do your background on the company too... "I read that you purchased company XYZ or landed XYZ contract.. how does the future of that affect my position..."
This is essential IMHO.

To follow-up on dawgfan's post...

How are assignments distributed within my group/team/department?
How does the group fit into the company as a whole? (This may be fairly obvious depending what the job is, but almost every company has a black sheep group that noone else at the company wants to deal with. Make sure you aren't getting into a situation like that.)

I always like -- "What does a typical day look like for someone in this role?"

I used to like asking how the interviewer got to the position in the company he/she is currently in. This way you can see how moving up the ladder works. This also allows you to get into some personal things with your interviewer which can help build the relationship.