I think that your current range of topics is great and certainly covers a broad spectrum but have you ever considered including Hobbies in your list, i have some particularly obscure ones and it would be great to have some related questions answered\discussed specifically by answerbank members.
We need some new ones. Someone suggested Aviation which could be popular.
I think a category called Abuse could be useful. It would give Ed somewhere to move loads of correspondence. Also anyone feeling like life was good could go there for a slagging off, to bring them back down to earth.
i think its time the ed added a note to the word 'topics' to show that 'click here to see a full list of sub ctagories' - then we wouldn't get people keep asking for topics to be added that we already have