As an interview candidate, what are the best questions that one should ask an interviewer?

The interviewee could ask the following questions :

1. Could you explain your Organizational Structure?

2.What are the day to day responsibilities of this job?

3.Could you describe about the Company's Management Style?

4. What particular Computer equipment and software do you use?

5.How will my responsibilities and performance be measured and by whom?

Questions must be very professional related to the Job and never ask about salary and benefits until and unless they are raised by the employer. Make it  a point that you will not ask questions wherein you can find answers in the employer's website.

well the best question is about ones Job surety