A very unimaginative and dangerous question. Meant as an icebreaker, this can also be a way of finding things out that the interviewer (at least in the US) is not legally supposed to ask. Keep this answer professional and brief. Prepare for it ahead of time. 30 seconds is plenty for this answer, so you can get on to the actual interview.

I agree with Mike that this is a loaded question, but oftentimes it is asked because the interviewer wants to get comfortable as well. As someone who has conducted a lot of interviews, this question is a great way to get things started.

Do NOT respond to this question with a question. I often heard this: Professional or Personal?

Again, I agree with Mike about 30 seconds. You should have a 30 second self-marketing commercial ready. It is a good idea to practice your commercial in front of a mirror or video tape it. Get comfortable and natural with this 30 second commercial use it for this question, but also use it when networking.

Here is a rough example of a 30 second commercial:

I am [name], the majority of my career has been in [your industry/field] (e.g. customer service, accounting). Most recently, I was with [company name]. Where I was [previous title]. I am particularly proud of [name a recent, relevant accomplishment].

Wherever I have worked, I bring three key strengths to the table:
[1] - hard skill
[2] - hard skill
[3] - hard skill (soft skill - if management or HR position)

I am currently looking for a position in the [industry name] where I can utilize my skills in [name a skill] and [name a skill].