The Questions Behind the Question
The interviewer wants to make sure you are genuinely interested in his/her company and are not just ‘taking a job’. You should state very specific things about the firm that attract you to the position, both in terms of what the firm needs and the different opportunities that the job would provide. What unique characteristics about the company make you prefer it over another? Can you differentiate the company from its competitors? Do you show the experience, skills and attributes that will make you a valuable contributor in the job? The interviewer will be looking for a thoughtful response to why you are interested and solid reasons to support that interest.
"I see an exceptional fit between what your organizations is looking for and what I can bring to the position. I’ve been impressed with your company’s performance in the enterprise software industry and the recent feature enhancements I’ve seen in your most recent product release. This type of innovation is something I value in an organizational culture and I try to bring this approach to my software design and programming work. In my current company I am taking customer feedback on what desired functionality they want to see in the next version of our software product and I'm creating the most user-friendly and customizable system available in the market. I want to use my programming skills to help your company to continue producing leading-edge software products.