During job interviews it seems common for the interviewer to ask something along the lines of "Why are you looking for a new job"? The last time I was asked this was during an interview where the company had approached me after finding me online. Not being prepared for this under the circumstances, I stumbled through an answer about not fitting in well with the group I work with (which, unfortunately is true). What would have been a better way to handle this question?
Edit: In the occasion mentioned above, I had not been actively seeking a new job, and since they had contacted me, I was going to the interview to see what might come of it. That said, this is a tricky question to handle, as answering with something like "My boss is a jerk" or "I want to make more money" (or "I don't fit in well with my group") can create questions in the interviewer's mind about your fitness for the job. Thus, I'm seeking some positive answers that can used.