Open Source Software as an alternative to commercial software

Why choose Open Source software?
When choosing an open source product, it has advantages for the user, not only will always be available for free, as can be improved by any programmer. An Open Source program can be changed and improved because they can have access to the entire source code, any user can make suggestions or report errors, and programmers are always open to feedback, is a software made ​​by all and for all, even creating communities dedicated to the improvement of certain programs, this benefits all.

Here I present a list of software with various categories and operating systems, which you can purchase for use as an alternative to commercial products, that not everyone can afford. The quality is not always equivalent to the commercial product, but in most cases it is sufficient for the needs of the user, or to the novice user start to learn how it works.

NAME	TAGS	OPERATING SYSTEM
Database
Apache Directory Server	java	Windows, Mac, Linux, Unix
Firebird	sql	Windows, Mac, Linux
MySQL	sql	Windows, Mac, Linux, Unix
OpenOffice Base	hsql, rad	Windows, Mac, Linux, Unix
SQLite	rdbms, slq	Windows, Mac, Linux, Unix
SQLTools	sql, oracle	Windows
SQuirreL SQL Client	sql	Windows, Mac, Linux
Web Development
Bluefish	html	Mac, Linux, Unix
Eclipse	ide, java	Windows, Mac, Linux, Unix
Komodo Edit	ide, html	Windows, Mac, Linux
XML Copy Editor	xml, dtd, xslt	Windows, Linux
Concrete5	website	Windows, Mac, Linux, Unix
IceBB	rss	Windows, Mac, Linux, Unix
KompoZer	html	Windows, Mac, Linux
Liferay Portal	web	Windows, Mac, Linux, Unix
Nucleus CMS	blog	Windows, Mac, Linux, Unix
OpenLaszlo	applications	Windows, Mac, Linux
phpBB	forum	Windows, Mac, Linux, Unix
Serna Free	xml	Linux
Graphic Applications
Archimedes	cad, svg	Windows, Mac, Linux
Blender	3d	Windows, Mac, Linux, Unix
BRL-CAD	3d, cad	Windows, Mac, Linux, Unix
Cinelerra	video	Linux
FreeCAD	3d, cad	Windows, Mac, Linux
Gimp	drawing	Windows, Mac, Linux, Unix
Inkscape	2d, vector, svg	Windows, Mac, Linux, Unix
K-3D	3d	Windows, Mac, Linux, Unix
MyPaint	painting	Windows, Mac, Linux
QCad Community Edition	cad	Linux, Unix
Internet and Network
aMSN	chat	Windows, Mac, Linux, Unix
Chrome	browser	Windows
Evolution	e-mail	Linux
FileZilla	ftp	Windows, Mac, Linux, Unix
FrostWire	bittorrent	Windows, Mac, Linux
HydraIRC	irc	Windows
Firefox	browser	Windows, Mac, Linux
Thunderbird	e-mail	Windows, Mac, Linux
Mumble	chat, audio	Windows, Mac, Linux
Nagios	monitoring	Windows, Mac, Linux
NeDi	monitoring	Windows, Mac, Linux, Unix
NeverNote	organizer	Windows, Linux
OpenNMS	monitoring	Windows, Mac, Linux, Unix
OpenVPN	encryption	Windows, Mac, Linux, Unix
OSXvnc	remote-desktop	Mac
Pandora	monitoring	Windows, Linux
Pidgin	chat	Windows, Mac, Linux
PuTTY	emulator	Windows, Linux
RSS Bandit	rss	Windows
RSSOwl	rss	Windows, Mac, Linux, Unix
VNC	remote-desktop	Windows, Linux, Unix
WengoPhone	chat, video	Windows, Mac, Linux
WIPFW	firewall	Windows
Wireshark	packet-sniffer	Windows, Mac, Linux, Unix
xVideoServiceThief	youtube	Windows, Mac, Linux
Zenoss	monitoring	Linux
Multimedia
Amarok	mp3, player, radio	Linux
Ardour	audio, recording	Linux
Audacity	audio	Windows, Mac, Linux, Unix
Avidemux	video-editing	Windows, Mac, Linux
Banshee	podcast	Linux
DVDStyler	dvd-authoring	Windows, Linux
Freevo	media center	Mac, Linux
HandBrake	dvd copy	Mac
Jokosher	audio, recording	Windows, Linux
Kedenlive	video-editing	Mac, Linux
Kino	video-editing	Linux
LMMS	audio, recording	Windows, Linux
MPlayer	media player	Windows, Mac, Linux
MuseScore	audio, composition	Windows, Mac, Linux
MusicBrainz	editing	Linux
Openshot	video-editing	Windows, Mac, Linux
Rosegarden	midi	Linux
Taksi	video capture	Windows
Traverso DAW	audio editing	Windows, Mac, Linux
VLC media player	media player	Windows, Mac, Linux, Unix
Security and Privacy
Anti-Spam SMTP Proxy	spam	Windows, Mac, Linux, Unix
BleachBit	clean up	Windows, Linux
Clam AntiVirus	anti-virus	Linux, Unix
ClamWin	anti-virus	Windows
FreeOTFE	encription	Windows
KeePass	password	Windows, Mac, Linux
TrueCrypt	encription	Windows, Mac, Linux
Winpooch	anti-virus	Windows
WIPFW	firewall	Windows
Wireshark	packet-sniffer	Windows, Mac, Linux, Unix
Utilities
OpenOffice	office	Windows, Mac, Linux, Unix
7-Zip	compression	Windows
Amanda	backup	Mac, Linux, Unix
Bacula	backup	Windows, Linux, Unix
Burn	burning	Mac
CamStudio	screencast	Windows
CDRDAO	burning	Windows, Linux, Unix
Clonezilla	disk-cloning	Windows, Linux
Cooperative Linux	virtual machine	Windows
Greenshot	screen capture	Windows
Sumatra PDF	pdf creator	Windows
VirtualBox	virtual machine	Windows, Mac, Linux
Xen	virtual machine	Windows, Linux
Xpdf	pdf	Windows, Mac, Linux, Unix
xvidcap	screencast	Linux