What software tools do you use in your scientific workflow?
Here are a few of my favorites:
eLabFTW - Excellent, Open Source Lab Notebook...better than the paid alternatives in my opinion
Plot2 - OS X Scientific Plotter
Zulip - Open Source Group Chat. iOS app needs help, but desktop is great.
Sublime Text 3 - Highly Extensible Text Editor
Firefox - duh!
Momentum - sort of off topic...but this plugin is a serious performance enhancer. Currenlty only for Chrome but supposedly coming to Firefox soon.