Hardware: Your average desktop PC
OS: Emacs
Boot loader: Debian stable
Languages: C, Python, JavaScript, Perl (and various others from time to time)
Other tools: git (along with git-flow and git-annex), zsh, gnus (mail reading; emacs), erc (irc; emacs), empathy (jabber), screen (on my various servers), kvm + virt-manager to manage my virtual machines
Frequently used programs from within my own software: glib, django, zeromq, mongodb, flask, jQuery, TAP::Harness