I've heard this question thrown at me several times during my career. If it were outside of career I can easily answer it.
Yesterday, I got into the same situation. I was asked about that one point that will make me stand out at work and also one point that would be my weakness. Did I stumble...not sure, but I was uncomfortable !
This question always bothers me. What is your experience? How would you answer this?
I remember the early days of my career when a few colleagues of mine had said 'Girls' as a response to this question !