Open Source for Windows part 1

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.
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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.
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IM - Instant Messaging

Pidgin

Connect to multiple IM accounts simultaneously in a single app, including: AOL IM, MSN, and Jabber.
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E-mail

Mozilla Thunderbird

Powerful spam filtering, solid interface, and all the features you need.
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RSS

RSSOwl

Solid cross-platform RSS client.
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Peer-to-Peer Filesharing

Cabos

A simple, easy to use filesharing program. Gnutella network.
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Gnucleus

A very good Gnutella search and download filesharing program.
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Azureus

A powerful, but complicated BitTorrent client. So many features you'll lose your mind.
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Video Playback

VLC

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

Similar to VLC-- plays loads of video formats.
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Media Player Classic

Compact, but powerful media player. Plays anything under the sun. No install necessary.
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DVD Ripping / Video Conversion

Media Coder

Great tool for ripping CDs, DVDs, etc and converting between tons of video formats.
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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.
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AbiWord

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

Juice

Solid podcasting client.
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DVD Ripping

Handbrake

DVD to MPEG-4 ripper/converter.
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Sound Recording

Audacity

Simple sound recording tool.
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Graphics / Photo Editing

GIMP

Photo editing application that rivals Photoshop in features.
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Paint.NET

Graphics editor with a very nice interface.
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Inkscape

Vector graphics application.
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FTP / SFTP

Filezilla

Excellent FTP program.
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IRC

X-Chat 2

IRC client.
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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.
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