The premier free, open-source browser. Tabs, pop-up blocking, themes, and extensions. Considered by many to be the world’s best browser.
Video Player / Video Podcasting
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.
IM – Instant Messaging
Connect to multiple IM accounts simultaneously in a single app, including: AOL IM, MSN, and Jabber.
Powerful spam filtering, solid interface, and all the features you need.
Solid cross-platform RSS client.
A simple, easy to use filesharing program. Gnutella network.
A very good Gnutella search and download filesharing program.
A powerful, but complicated BitTorrent client. So many features you’ll lose your mind.
Plays more video files than most players: Quicktime, AVI, DIVX, OGG, and more. Pretty good interface.
Similar to VLC– plays loads of video formats.
Media Player Classic
Compact, but powerful media player. Plays anything under the sun. No install necessary.
DVD Ripping / Video Conversion
Great tool for ripping CDs, DVDs, etc and converting between tons of video formats.
Word Processing / Office Suites
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.
A word processor. Leaner and quicker than OpenOffice. Compatible with Microsoft Word documents and OpenDocument Format.
Solid podcasting client.
DVD to MPEG-4 ripper/converter.
Simple sound recording tool.
Graphics / Photo Editing
Photo editing application that rivals Photoshop in features.
Graphics editor with a very nice interface.
Vector graphics application.
FTP / SFTP
Excellent FTP program.
_____________________________________________________________Reprinted from Open Source Windows