Tristan Rhodes writes "List Of Open-source Programs (LOOP) for Microsoft Windows Operating Systems
What is the LOOP list?
This is a list of high-quality, open-source applications that run on Windows. Feel free to edit and add any programs to this list that meet the criteria below.
To demonstrate the quality of open-source applications and thereby advocate the open source software development model.
Tell all your non-Linux friends and family about the LOOP list. On this list they will find high-quality replacements for the software that they have purchased/pirated. Once they become familiar with these new applications, introduce them to your favorite Linux distribution (mine is Ubuntu). Then help them convert to Linux, using the applications that they became familiar with on Windows.
Rules for adding programs to the LOOP list:
1. Must be open-source.
2. Must run on Microsoft Windows operating systems.
3. Only include the best application for each specific purpose. In rare cases, two applications may be listed.
4. Include the names of the top three commercial applications that provide similar functionality, if known."