Here’s a quick list of the most usefull open source or free apps out there that make everyday computing on a Mac enjoyable.

1. Firefox
The most obvious one. Not the fastest among all browsers but extremely customisable with all the available extensions and themes.

2. Skype
The Mac version recently got updated and now has video calls enabled.

3. Vienna
The best RSS reader by far for OS X and a big help to keep track of a large number of websites.

4. NeoOffice
Unless you work with your Mac in an office environment that requires MS Office you’ll find everything you need and much more in this very cool suite.

5. MPlayer
The media player that takes care of most formats. Use Quicktime with the Flip4Mac extension for the few WMV clips that don’t work with MPlayer.

6. Transmission
A very simple torrent application for those legal downloads.

7. Google Earth
This gets better and better with the improvements of the satellite imagery and new features.

8. Blender
A very powerful 3D modeling application.

9. Phoenix Slides
A fast image browser that enables you to view large amounts of pictures with ease.

10. Everything that is already on your Mac when you buy it. I know it’s not really free but those neat apps do cover a lot of tasks already.