This is one of my favourite questions. As far as an employer is concerned, this represents the crux of the whole interview. This is your chance to shine, by saying exactly why you decided to apply for the job. You will need to bring out your particular strengths and show clearly what you can offer not what you want to get from the job. Quoting your experience and skills will help to impress on the employer that you will be a valuable addition to the team. Don’t forget to include good points about your personality here. Move on to explain how you would use all these things to help build on the success of the organisation.
Take care not to appear arrogant. Even if you can see weaknesses in some of the present activities or direction of the organisation, you should only convey these in terms of what could be improved. You need to be very aware of your audience. The Marketing Director of a large company asked a candidate at an interview to comment on the latest marketing campaign. The candidate effectively ruled herself out of the job when she answered that she thought the work had been complete rubbish from start to finish. None of us responds well to negative criticism, whereas constructive and creative points are often well received.