Stack Overflow
Q&A for professional and enthusiast programmers
Super User
Q&A for computer enthusiasts and power users
Unix & Linux
Q&A for users of Linux, FreeBSD and other Un*x-like operating systems
Area 51
Q&A for proposing new sites in the Stack Exchange network
Server Fault
Q&A for system and network administrators
Web Applications
Q&A for power users of web applications
TeX - LaTeX
Q&A for users of TeX, LaTeX, ConTeXt, and related typesetting systems
Board & Card Games
Q&A for people who like playing board games, designing board games or modifying the rules of existing board games
Software Recommendations
Q&A for people seeking specific software recommendations
Code Review
Q&A for peer programmer code reviews
Blender
Q&A for people who use Blender to create 3D graphics, animations, or games
Vi and Vim
Q&A for people using the vi and Vim families of text editors
Mathematics
Q&A for people studying math at any level and professionals in related fields
Science Fiction & Fantasy
Q&A for science fiction and fantasy enthusiasts
Meta Stack Exchange
Q&A for meta-discussion of the Stack Exchange family of Q&A websites
Android Enthusiasts
Q&A for enthusiasts and power users of the Android operating system
Woodworking
Q&A for professional and amateur woodworkers
Electrical Engineering
Q&A for electronics and electrical engineering professionals, students, and enthusiasts
Physics
Q&A for active researchers, academics and students of physics
Arqade
Q&A for passionate videogamers on all platforms
Software Engineering
Q&A for professionals, academics, and students working within the systems development life cycle