Answer with a question, i.e., "What is the salary range for similar jobs in your company?" If they don't answer, then give a range of what you understand you are worth in the marketplace.
What do you know about our company?
Do your homework before the interview! Spend some time online or at the library researching the company. Find out as much as you can, including products, size, income, reputation, image, management talent, people, skills, history and philosophy. Project an informed interest; let the interviewer tell you about the company.
How much do you expect, if we offer this position to you?
Be careful; the market value of the job may be the key answer, e.g., "My understanding is that a job like the one you're describing may be in the range of $______."
What kind of salary are you worth?
Have a specific figure in mind ... don't be hesitant.