I usually answer "presentation skills" to this question. First, many of the jobs I apply for as a Software Developer don't require me to make formal presentations. Some have, but most don't. If you're applying for a position in sales or marketinig where formal presentations are part of the job, then this probably wouldn't be the best answer to give. Second, most people understand that getting in front of people is a nerve-wracking experience. Even if the interviewer happens to be good at giving presentations, most will still understand that the majority of people don't like to get up and be the center of attention in a formal environment.