For me there are two ways of answering this question,
- What am I qualified in and could teach?
- What do I enjoy doing that I would love to teach?
To answer the first interpretation, I have a degree in Physics and have in my distant past taught maths and physics at a secondary school in West Africa (High School) and I did enjoy it to an extent. I would never teach here in the UK, it would be a nightmare, but I imagine if you were teaching students who wanted to learn it may be rewarding. I used to like marking best and timetabling (as I was in charge of that) and as many bad days were met with good.
The second one...hmmm...let me see now...I can be quite patient, and would like to teach crafts but probably would enjoy doing arts and crafts projects with primary school children (age 4-8) a opposed to adults and such. However, if I could teach anything, I think English as a foreign language would appeal to me the most and I have toyed with doing a course in the past, so who knows!
What about you? Are you or were you a teacher? What would you like to teach?