Free And Open-source Software

Web Browsing

Mozilla Firefox The premier free, open-source browser. Tabs, pop-up blocking, themes, and extensions. Considered by many to be the world's best browser. Download Page

Video Player / Video Podcasting

Miro Beautiful interface. Plays any video type (much more than windows media player). Subscribe to video RSS, download, and watch all in one. Torrent support. Search and download from YouTube and others. Download Page

IM - Instant Messaging

Pidgin Connect to multiple IM accounts simultaneously in a single app, including: AOL IM, MSN, and Jabber. Download Page

E-mail

Mozilla Thunderbird Powerful spam filtering, solid interface, and all the features you need. Download Page

RSS

RSSOwl

Solid cross-platform RSS client. Download Page

Peer-to-Peer Filesharing

Cabos A simple, easy to use filesharing program. Gnutella network. Download Page

Gnucleus A very good Gnutella search and download filesharing program. Download Page

Azureus A powerful, but complicated BitTorrent client. So many features you'll lose your mind. Download Page

Video Playback

VLC Plays more video files than most players: Quicktime, AVI, DIVX, OGG, and more. Pretty good interface. Download Page

MPlayer Similar to VLC-- plays loads of video formats. Download Page

Media Player Classic Compact, but powerful media player. Plays anything under the sun. No install necessary. Download Page

DVD Ripping / Video Conversion

Media Coder Great tool for ripping CDs, DVDs, etc and converting between tons of video formats. Download Page

Word Processing / Office Suites

OpenOffice.org Big, full featured suite of tools for word processing and spreadsheets. Compatible with and a free replacement for Microsoft Word documents. Also supports OpenDocument Format. Download Page

AbiWord A word processor. Leaner and quicker than OpenOffice. Compatible with Microsoft Word documents and OpenDocument Format. Download Page

Podcasting

Juice Solid podcasting client. Download Page

DVD Ripping

Handbrake

DVD to MPEG-4 ripper/converter. Download Page

Sound Recording

Audacity Simple sound recording tool. Download Page

Graphics / Photo Editing

GIMP Photo editing application that rivals Photoshop in features. Download Page

Paint.NET Graphics editor with a very nice interface. Download Page

Inkscape Vector graphics application. Download Page

FTP / SFTP

Filezilla Excellent FTP program. Download Page

IRC

X-Chat 2 IRC client. Download Page

Archiving

PeaZip Fantastic archiving utility to extract and pack archives of an extensive amount of formats. PeaZip also features password protecting archives, keyfile support, system integration, a lovely interface, and much more. Download Page

Some more specialized free and open-source Microsoft Windows apps.

Note Taking Freemind An innovative application for note taking and outlining. Takes time to get used to, but some people swear by it. Download Page

Jarnal Open Source note taking application written in Java Download Page

Keynote Open Source note taking application, very good. I use this myself extensively Download Page

Personal Finance

TurboCASH Simple, easy to use application for managing personal finances. Download Page

Quasar Easy to use Accounting package Download Page

Chat Clients

aMSN MSN Messenger client written in TCL/TK aMSN Messenger

X-Chat IRC Client X-Chat

More Web Browsing

K-Meleon Fast, nice web browser. Download Page

Amaya Browser for Windows W3C developed web browser and editor for multiple platforms Download Page

Screensaver

Electric Sheep Immersive, trippy screensaver. Download Page

More Filesharing Frostwire GNUTella client based on the Limewire codebase. Download Page Also see: Poisoned - Azureus

3D Graphics and Modeling

Blender Powerful 3D Modeling software. Download Page Also see: Kerkythea (illumination engine) - Persistence of Vision Raytracer - Quesa

Stars and Outer Space

Celestia Open-source 3D planetarium software. Akin to traveling through space (outer space). Download Page

Stellarium "Renders realistic skys in realtime." See what you would see if your city wasn't so light-polluted. Used in real planetariums. Download Page Also see: macORSA - Orbit Reconstruction, Simulation, and Analysis

Games Marathon: Aleph One

Engine for Bungie's free FPS series Marathon. Play online, solo play with rich original story, many total conversions and thousands of maps. Download Page

Zombies 3D zombie strategy game. Download Page

Armagetron Advanced 3D Tron game. Download Page

BZFlag First-person tank game. Download Page

Battle for Wesnoth Fantasy / Strategy Game Download Page Also see: Snes9X (SNES emulator), Frozen Bubble

Free File Hosting

CC Publisher Host Creative Commons video or audio files for free on archive.org with this easy uploader. Download Page

Security Tools NMap Easy to use port scanner for Windows Download Page

Wireshark Network Protocol Analyzer, formerly called Ethereal Download Page

TrueCrypt Creates encrypted virtual hard drives for extra security Download Page

ClamWin Open Source Anti-Virus. Very good at detecting viruses. Can be plugged into hMailServer for email protection LIMITATION: Real Time scanning not implemented yet Download Page

Eraser Delete files securely off your hard drive utilizing DoD standards Download Page

MP3 and Audio Tools MP3 Gain Easy to use MP3 manipulation tool for Windows. adjusts sound levels on MP3's so they are all the same Download Page

MP3 Book Helper This program provides rapid Mp3 (ID3v1, ID3v2) and Ogg/Speex/Flac Vorbis tags editing and file renaming functions. Mass Tag editing is done using special variables and Regular Expressions. Download Page

musikCube Open Source MP3 Player, ripper and organizer written using the .NET Framework Download Page

Utilities Cobian Backup Backup software. Download Page

7-Zip File archiver. Download Page

Developer tools XEmacs The classic, super customizable editor, for Windows. Download Page

KompoZer Easy to use, open source WYSIWYG html editor Download Page

SharpDevelop Open Source IDE for the .NET Framework. Utilizes the multiple programming languages and Windows forms Download Page

Notepad ++ Open Source programmers notepad for Windows Download Page

SciTE Source code Editor for Windows and X Download Page

Web Developer Server Suite Very good WAMP Stack (Windows, Apache, MySQL, PHP) Very thouroughly tested on Windows Server 2003 and Windows 2000 Server (preliminary testing on Longhorn Server underway). Highly Recommended. Download Page

Mapping Tools Nasa World Wind Mapping tool similar to Google Earth for Windows. Must have the .NET Framework installed. Download Page

Other Graph (graph plotting software) Startup Manager (pick what you want to launch on startup) freeotfe "on-the-fly" transparent disk encryption program for PCs and PDAs.