Development
Local setup is MacBook, Coda, MAMP, Navicat to manage MySQL, Git or SVN depending on project.
Staging area is on my development server (LAMP) or on client-provided hosting.
For starting projects I have a base template and module set that includes most of what I put into projects.
Modules
Just started using Alan's Commerce Bug. I plan on looking into MageTool soon.
I use Unirgy's Gift Cert and Store Locator often.