Great open source software.

I try my hardest to not spend any money and get the most out of something, some people call this being cheap but I like to think of it as being cost efficient. Most people know of a free alternative to something but not a lot know that there is probably an open source equivalent to anything.
My list will illustrate some of the best open source things to get your work done or waste your time with.

To start I will get the known out of the way.
Open office


Open office is a free equivalent to microsoft office boasting word, powerpoint, access and excel, it even has it's own quirks of an image manipulation program and an advanced calculation program. Being a hefty 200mb download and about 400mb on disk it is still the better use because if you can't afford office yet you have hundreds of .doc or whatever from school. Open office can still read and manipulate office docs for use back in office, how cool is that.

Sumatra PDF


Some people may or may not be aquianted with a PDF file, these files are very genius. The most renown for a PDF veiwer is Adobe's Acrobat. Even though Acrobat is free it has a very load slow time and can be very clunky. Sumatra is a very versitile PDF viewer being light weight and easy to use. A must have.

Audacity


Audacity is an open source audio editor which is easy to use and very versatile in it's functions. I use this alot for production of music and podcasts/internet radio and the like. It's a wave length editor and multi media recorder.

Construct

Construct is an open source directX sprite powered game creator, create anything from a 2D side scroller to a Pseudo 3D FPS game. Using basically drag and drop commands and a paint.net style sprite creation this program is very fluid and easy to use. Side by side to game creation it can also make a variety of programs from media players to .dll's.


Paint.net/GIMP


Both of these are open source equivalents to photoshop.

Winamp


Winamp is a media player with a huge compatibility rate. It supports anything from MP3 to Ogg Vorbis and AAC. With a plugin catalogue comparable to that of firefox it can be turned into anything you want your media player to do. (I host an internet radio station using it). It can also manage external data like Ipods and other mp3 players.

VLC


VLC is the winamp of videos, it plays anything from AVI to MKV and 3GP. I have YET to find a video file not compatible with this player. It also has the same compatibility with music making this the best media player out there. The best part is that it is lightweight, almost half of that of say WMP and iTunes