Aquamacs is a distribution of the well-known and powerful Emacs text editor. Developed by David Reitter, it looks just like a Mac app and runs like one. However, it retains the power of GNU Emacs. In short, it brings you the power of Emacs as well as the configurability but with an easier to use interface.
Kompozer is a free web authoring tool that offers a complete set of features for WYSIWIG editing of web pages, web file management and performing other tasks. As envisioned by the Kompozer team, it’s a fully furnished system but easy to use, and ideal for non-technical people who want to produce a professional looking site without needing to learn coding.
Brackets is a free open source web development tool designed for front end developers and professional web designers. While there are plenty of web editors around, Brackets differs because it combines all the essential tools in the editor as you’re coding. It also saves all the changes you make automatically without the need to reload, but there’s more.
VSDC Video Editor from Flash Integro is a free video editing program but with features that rival those of pricey, professional applications. If you are looking for powerful software to edit videos, this is for you. While there is a learning curve, it is worth investing time here since there’s a lot you can do with it.
Zim is an open source text editor that you can use to take down notes and gather your thoughts. Developed by the Zim Wiki Team, it is easy to use and powerful editor that lets you to set up and link wiki pages. If you're tired of the very basic notepad that comes with your OS, then give this a try.
XCode is a free application from Apple that will give programmers and developers all the tools they need to create quality apps for the Mac, iPad and iPhone. There are a lot of interesting and useful features here, but the integrated user interface makes coding, debugging and testing a breeze. And that is just for starters.
LIVES is a free video editor developed by Gabriel Finch for Linux. This application, which can also be used by video jocks, has many powerful features like real time capture, trimming and resizing of video clips, and de-interlacing. However, the interface makes the features very accessible.