Personally, these are a few of what I use: BeyondCompare to compare files. 7Zip to work with zip and tar archives. Notepad++ to edit my scripts and source code. ClamWin to detect viruses on my machine. Malware Bytes to keep the system clean from malware CCleaner for registry maintenance. Defragler for defragmenting disk drives. Putty to remotely connect via ssh. Ext2Fsd to view my linux ext4 partitions. FileZilla for remote file transfer. WinSCP (Haven't tried this yet). LibreOffice to work with spreadsheets and documents. Git for checking in code and also get some bash utils (like ls, cp, ssh, etc.). ConEmu to get a linux-like console. GIMP for working with raster graphics. InkScape for working with vector graphics. Would love to hear about more useful ones that others are using!