Internet and communication utilities
ABC - Another Bittorent program
aMSN - MSN messenger clone. Linux, OSX, Windows compatible.
AMule - A P2P client for the E2K and Kad networks.
Avant Browser - Multi-window browser, which adds a batch of features and functionalities to Internet Explorer.
Azureus - A very good BitTorrent client
BitComet - a BitTorrent/HTTP/FTP download management software.
DownThemAll Firefox Extension - Download all links off a page. Customizable. Useful for offline reviewing of sites.
eMule - Server and non-server based P2P
FeedReader - An RSS reader that can also download podcasts/videocasts.
FileZilla - Open source FTP program - FileZilla is a fast and reliable FTP client and server with lots of useful features and an intuitive interface.
Firefox - Good open source web browser
LifeRea - A Linux clone for FeedReader
mIRC - One of the best IRC chat clients available for Windows. Free to try, but a full license costs 20$ (Shareware)
Opera - Another good web browser
Pidgin - A good open-source instant messenger program. Formerly known as GAIM.
PuTTY: A Free Telnet/SSH Client - PuTTY is a free implementation of Telnet and SSH for Win32 and Unix platforms, along with an xterm terminal emulator.
Skype - Free talk, chat and videochat. For a charge, you can also talk to standard phone lines.
Thunderbird - open source email client from Mozilla
UltraVNC - Allows you to remotely access your computer from any Internet-connected computer in the world.
uTorrent - Small Bittorrent utility
WinSCP - Open source freeware SFTP/SCP client for Windows.
XChat - A good and free client for IRC chat.