I mostly do lighting design and direction, but lately I've taken to doing some tech directing and stage management work as well. I started off with lighting design and have been a techie since the age of 12.
I went to college for theatrical design and technical production and am now a paid professional. A union member and everything. Though I can't stand being referred to as a "techie". Was there more to this question or were you just taking a poll?
I'm Lighting designer, Sound designer, special effects designer, and former pyrotechnician (before the laws changed and made it impossible to freelance as an individual).