Hobby, addiction, passion...probably in this order.
While is see domaining, developing sites in the near future as a possible business venture to get myself into, my real talent lies in evaluation, marketing and positioning domains. Lately, more than ever, i've come to the conclusion that without programming talent, its pretty difficult to create a profitable venture. The waiting times for programmers to actually get work done are exorbitant, the reliability leaves much to be desired and the success is heavily depending on the programmers talent to visualize the concept and build a functional site.
Before i go completely off target here, domaining is great, and with the right tools it's definitely a gold mine.