Technologies I work with: Node.js, Scala, Java, Python, Android
OS: Ubuntu (Xubuntu) 12.04, Windows 7
IDE: IntelliJ IDEA - Consistent across various technologies and perfect for large code bases
Text Editor: Sublime Text 2 - Pretty damn awesome, even with large files
Terminal: Terminator
Hardware: Last gen MacBook Pro (15" with matte screen), iPhone 4.
Operating systems: Mountain Lion, iOS 5.
Development tools for web apps: Terminal.app, bash, vim (for Sinatra apps), TextMate (for Rails apps), git, GitHub, Ruby 1.9.3, Sinatra (with DataMapper and Haml), Rails, jQuery, Google Chrome. In my experience, vim is better for projects with fewer or larger files, and TextMate is better for projects with more or smaller files.
Production environment: Heroku Cedar stack, Heroku Postgres, Amazon RDS, Amazon S3, Amazon CloudFront, MemCachier (through Heroku), New Relic (through Heroku for profiling/performance info).
Development tools for Android apps: Eclipse, git, GitHub. I hate Eclipse, but I haven't found a better way to develop Android apps.
Windows 7 with VS2010, solarized theme.
Calcium SDK for MVVM development.
Unit tests: Jeff Wilcox's Silverlight Unit Test Framework (WP7 SDK doesn't have unit tests built-in).
Test device: a Lumia 800. The emulator doesn't work well on my machine.
Source control: git (command line, no VS plugins) and GitHub.
I occasionally also use my Macbook 13" with TextWrangler for writing some code when I can't access my main PC or when I want to make some fast fixes.
Macbook Air 13" (OS X ML) + Thunderbolt Display 27".
Terminal: Terminal.app, zsh, oh-my-zsh. Solarized theme.
Editor: Vim, Janus, bunch of plugins. With Solarized theme too.
Technologies: Ruby, Rails. MongoDB, Redis, Node.js, Backbone, CoffeeScript.
Deployment: Heroku.
Hardware: Lenovo T400, 8GB RAM, Core 2 Duo (due upgrade) + 50" Samsung Plasma display.
OS: W7 x64, OS X ML.
Platforms: Android, iOS, Blackberry Playbook Android emulator.
Technologies: Java, Objective-C, PHP, JSON, Google App Engine.
Unit testing on Android: Robolectric.
IDE: Eclipse and Xcode.
Deployment: Google Play Store, App Store.
MacBook 17'' Editor: SubEthaEdit, XCode for iPhone, Eclipse for Android Languages: Rails, Redis, Objective C, Python Infrastructure: EngineYard