FileZilla is a cross-platform graphical FTP, FTPS and SFTP client a lot of features, supporting Windows, Linux, Mac OS X and more. FileZilla Server is a reliable FTP server for Windows.
A fast multi-track audio editor and recorder for Linux, BSD, Mac OS, and Windows. Supports WAV, AIFF, Ogg, and MP3 formats. Features include envelope editing, mixing, built-in effects and plug-ins, all with unlimited undo.
PortableApps.com allows you to carry your favorite computer programs and all of your bookmarks, settings, email and more with you on a portable device (USB flash drive, iPod, portable hard drive, CD, etc) and use them on any Windows computer.
Shareaza is a multi-network peer-to-peer ( P2P ) file-sharing client supporting Gnutella2, Gnutella, eDonkey2000 ( eMule ), HTTP, FTP and BitTorrent protocols. Using C++, MFC and ATL, for Windows.
Pidgin is a GTK+ instant messaging application for Windows and Unix. It supports AIM, ICQ, Jabber/XMPP, MSN, Yahoo!, Bonjour, Gadu-Gadu, IRC, QQ, SILC, SIMPLE and more. See http://pidgin.im/about for more information.
A very nice MSN compatible messenger application, aMSN Messenger is a multiplatform MSN messenger clone. Works pretty much like its Windows based counterpart. Perfect for keeping in touch with those friends who have not yet seen the light. Works on linux
WinSCP is a SFTP client and FTP client for Windows. Its main function is the secure file transfer between a local and a remote computer. It uses Secure Shell (SSH) and supports, in addition to Secure FTP, also legacy SCP protocol.
MinGW: A native Windows port of the GNU Compiler Collection (GCC), with freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality.