Anti-Virus:

AVG Free - http://free.grisoft.com/doc/28415/lng/us/tpl/v5

Avast! Antivirus - http://www.avast.com/

AntiVir - http://www.free-av.com


PDF Reader:

Foxit Reader - http://www.foxitsoftware.com/


PDF Creation:

PDF Creator - http://sourceforge.net/projects/pdfcreator/


Media Players:

VLC - http://www.videolan.org/vlc/

Media Player Classic - http://sourceforge.net/projects/guliverkli/

Foobar2000 - http://www.foobar2000.org

ffdshow - http://www.free-codecs.com/download_soft.php?d=2541&s=65

Quicktime Alternative - http://www.free-codecs.com/download_soft.php?d=2829&s=66


Web Browsers:

Firefox- http://www.getfirefox.com

Opera - http://www.opera.com

K-Meleon- http://kmeleon.sourceforge.net/wiki/index.php?id=Download


Email:

Thunderbird - http://www.getthunderbird.com


Bit-Torrent Client:

uTorrent - http://www.utorrent.com/


Anti-Spyware:

Spybot: Search and Destroy - http://www.safer-networking.org/

AdAware SE - http://www.download.com/Ad-Aware-SE-Person...tml?tag=lst-0-1


IM:

Gaim: http://gaim.sourceforge.net

Trillian: http://www.trillian.cc

Meebo: http://www.meebo.com

Miranda IM: http://www.miranda-im.org


Firewall:

Comodo Firewall Pro http://www.personalfirewall.comodo.com/


Encryption:

Truecrypt

Network Analyzer:

Wireshark

ID3 Tagging:

EasyTag

GPU Overclocking:

ATITool <- works for nvidia cards also

Debugging:

Datarescue IDA Pro

OllyDBG

CSS Encryption Removal:

DVD43

FTP clients:

SmartFTP

Online File Storage:

Gmail File Server use your existing gmail account to store files online.

These are just Suggestions. I imagine there are more. If you have any, please copy my post adding yours under the correct heading to avoid members having to go through every post to see changes.