My current specialty has been ruby, rails, TDD, and their related shiny tools. I'm also never one to shy-away from a good sysadmin horror story.
Server Fault
Q&A for professional system and network administrators
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems.
Drupal Answers
Q&A for Drupal developers and administrators
Bicycles
Q&A for people who build and repair bicycles, people who train cycling, or commute on bicycles
Ask Different
Q&A for power users of Apple hardware and software
Photography
Q&A for professional, enthusiast and amateur photographers
Meta Stack Overflow
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
User Experience
Q&A for user experience researchers and experts
Programmers
Q&A for professional programmers interested in conceptual questions about software development
Answers OnStartups
Q&A for entrepreneurs looking to start or run a new business
Quantitative Finance
Q&A for finance professionals and academics
Area 51
Stack Exchange Network staging zone, where users come together to build new Q&A sites
