A biology major who slipped into web development and thence into web QA for Connexions, an open educational content site at my alma mater of Rice University. Now doing bioinformatics at Baylor College of Medicine's Human Genome Sequencing Center.
Stack Overflow
Q&A for professional and enthusiast programmers
English Language Learners
Q&A for speakers of other languages learning English
Super User
Q&A for computer enthusiasts and power users
Server Fault
Q&A for system and network administrators
Biology
Q&A for biology researchers, academics, and students
English Language & Usage
Q&A for linguists, etymologists, and serious English language enthusiasts
Role-playing Games
Q&A for gamemasters and players of tabletop, paper-and-pencil role-playing games
Aviation
Q&A for aircraft pilots, mechanics, and enthusiasts
Ask Different
Q&A for power users of Apple hardware and software
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Computer Science
Q&A for students, researchers and practitioners of computer science
Worldbuilding
Q&A for writers/artists using science, geography and culture to construct imaginary worlds and settings
Graphic Design
Q&A for Graphic Design professionals, students, and enthusiasts
Cross Validated
Q&A for people interested in statistics, machine learning, data analysis, data mining, and data visualization
Bioinformatics
Q&A for researchers, developers, students, teachers, and end users interested in bioinformatics
Academia
Q&A for academics and those enrolled in higher education
Personal Finance & Money
Q&A for people who want to be financially literate
Retrocomputing
Q&A for vintage-computer hobbyists interested in restoring, preserving, and using the classic computer and gaming systems of yesteryear
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites