11) Tux Paint Very useful for educational environments on a budget, Tux Paint is a simple-to-use drawing program designed for kids 3-12 years of age.
12) PDFCreator Create PDF files without the need for Adobe's software, using this open source alternative. Encrypt, auto-save and even create images with this software.
13) Grisbi Create, update and manage a number of personal accounts using the Grisbi software for Windows and Linux. Software is provided for free with a complete manual.
14) Evolution Perhaps the single most complete PIM since Outlook for Windows, Evolution provides full access to a calendar, email and personal tasks. Another consideration is its solid support for Microsoft Exchange server connectivity.
15) FreeMind Similar in many aspects to other closed source 'Mind Mapping' software, FreeMind allows the user to write with more of a 'whiteboard feel' than other applications. Perfect for tracking the flow of thoughts as they come to you.
16) Open Workbench Open Workbench offers featured-filled scheduling and other project management tools. Free to use, even for commercial use.
17) GIMPShop Built out of frustration with the cost of Photoshop and the existing UI provided by GIMP, GIMPShop enables graphic editing comparable to a Photoshop feature layout.
18) Dia Diagram creation similar to what you might find with Visio, but at zero cost to the end user. While it remains in active development and may turn up some bugs along the way, the application is strong enough for everyday use.
19) Synfig Generally described as an industrial strength vector-based animation utility, Synfig provides powerful features to those in animation using vector graphics.
20) Blender 3D modeling software providing the user with professional results. Wire-framing, texturing, Blender will do practically anything needed for 3D modeling.