Although each of these applications could be in a category of its own - such as "Office Suites", "Text Editors", or "Virtualization" - I just don't have enough recommendations to justify that.  So... here they are on the "Miscelaneous" page.

libreoff LibreOffice An application suite like MS Office including:
Writer - A word processor like MS Word
Calc - A spreadsheet like MS Excel
Impress - A slide-show tool like PowerPoint
Draw - A graphics editor like MS Visio
Base - A database tool like MS Access
In the future, LibreOffice could re-merge with its OpenOffice cousin, but as OpenOffice seems to be circling the drain, that doesn't seem very likely.  
winscp WinSCP An FTP and SCP file management tool that includes a full explorer or commander-like interface that even allows remote editing. I have trouble imagining a better file transfer tool.
putty PuTTY Terminal emulation through Telnet, SSH, and serial ports. Plenty of behavior and connection options, but limited DEC terminal emulations (only VT100+ and VT400).
npplus Notepad ++ A much more versatile replacement for the Notepad included with Windows. Includes many language-sensitive cues and blocking capabilities. Could almost be considered a development environment - but not quite.
 Joomla A Content Management System that somewhat insulates a designer from hand-coding and architectural issues that distract from content development.  With respect to WordPress and Drupal, Joomla is good balance between ease-to-use and customizable.  This site relies on Joomla for back-end processing and provides a decent management interface for the author (me).

foxit Foxit Reader

An excellent, compact PDF reader that installs almost instantly and runs faster than Adobe Reader. It’s also better for filling out and saving forms. It even includes free-hand markup tools, text conversion capabilities, and a virtual printer for creating PDF files.
 VirtualBox Oracle's well supported hypervisor allows a wide range of hosts and guest operating systems.  Some features include hardware-assisted virtualization, snapshots, guest extensions, and network share emulation for host access. In addition to it's own "VDI" disk images, it can use ones created for VMWare (VMDK) and Microsoft's Hyper-V (VHD).  Extensions supporting USB 2.0, RDP, and PXE require a license only for commercial use. 
Turnkey Linux

In combination with a hypervisor like VirtualBox or VMWare, Turnkey Linux virtual appliances greatly simplify installation and testing for a wide range of products.  These include Wordpress, Joomla, Drupal, OpenVPN, OpenLDAP, GIT, OwnCloud, Sugar CRM... and over 80 other pre-built servers.

Easily one of the most useful and timesaving resources in existence.  It literally takes 5 minutes to install and start running most of the appliances.  My Joomla development environment is hosted on one of these running in VirtualBox on my desktop.