Note Taking Software
OneNote vs Evernote – My take on the difference between the two and how I use both of them (together).
Mendeley – It is one of the best referencing and PDF management software. The only drawback is that it is not really open-source and owned by Elsevier. It is still Free though, just not open-source
Zotero – It is free and open source, which might it better than Mendeley. However it is 2nd to Mendeley to me in terms of overall experience.
Python – High-level programming that can be used for various data analysis (with the addition of libraries such as SciPy etc). In my opinion the advantage that it has over R, is that it can also be used for automation and other things than just pure data analysis.