Some softwares...

Operational system: either Mac or Linux.
LaTex for Mac: MacTex
Bibtex manager:  Bibdesk (Mac), Kbibtex (Linux).
LaTex front end editor for Mac: TexPad 
Symbolic & numerical computation: Mathematica 
General purpose text editor (not word editor): TextWrangler
Cloud backup and syncing among different computers: SpiderOak & Dropbox
Presentations: Keynote + LaTeXiT (Sorry Beamer... )

Fun...

 xkcd. And if you don't get it,  this helps sometimes.

Search engines...

General purpose: DuckDuckGo, Google
Scientific: InSpire, Nasa ADS, Google Schoolar