| Linux Kernel | Yes, indeed, that is the one Linus Torvalds created some 18 years ago. |
| Ubuntu | The best-known Linux distro out there. And for the most part for a good reason. |
| Linux Questions | A great forum for asking your questions about Linux! |
| Firefox | The heavy-weight champion. Fully featured and extensive, and a huge resource hog. |
| Konqueror | Somewhere in-between Firefox and Google Chrome. Good for occasional surfing, but is actually a much better used as file browser. |
| Opera | Good alternative, especially for mobile devices (Opera Mini). Also now features Opera Unite, if you are into that sort of thing, I guess. |
| Google Chrome | Fastest and leanest browser of them all. Very nice. |
| Blender | OpenSource 3D suite of fantastic complexity, a well of features and a great community. |
| Inkscape | Poor man's vector drawing program. Misses Illustrator's quality by a mile, but is still damn useful in certain circumstances. |
| Last.fm | A great social music site but with the best feature being statistics collection. Unfortunately now utterly commercialized. |
| Rockbox | Opensource firmware for a number of mp3-players, including Apple's line of products. Enables many advanced and interesting features (including games like Doom 1 and 2, playlist sorting, queues, playlists etc.) |
| Wordpress | Probably the best blog publishing software (and to a certain degree Contents Management System) out there. |
| ZenPhoto | A lightweight easy-to maintain and use gallery picture gallery coded in PHP. |
| Twitter | Microblogging site. If you haven't heard of it, you must have been living under a rock. No, seriously. |
| Youtube | Currently the king of user-added video sites out there. Unfortunately not always as good as claimed. |
| Viddler | A great alternative to Youtube. |
| Open Office | The most fully-featured opensource office suite out there. Can easily act as a replacement for Microsoft Office. |
| Google Apps | Very useful if you "live" online, includes PIM applications as well as Office software. |
| KDE | One of the two great desktop environments in the Linux world. |
| Openbox | A fully-featured yet minimalistic (although not extreme as RatPoison or EvilWM) window manager. |
| Conky | The most feature-rich system monitor for Linux. It will however not win any awards for visual stylishness. |
| Wine | Allows the user to run Windows application on a Linux desktop. Sometimes it will run, sometimes it won't - although admittedly it has been doing more latter in the past few years. Kudos goes to the Wine community! |
| NoMachine NX Client/Server | Great remote desktop software enabling low bandwidth consumption through compression and some other neat features. |
| Hamachi | Virtual LAN software, also works fine on Linux. Great for gaming. |
| Firebug | A must-have extension for web developers. |
| YSlow | Performance analysis add-on for Firebug. |
| RIP | Gives you a wealth of advanced features on removing certain contents from web pages. Nice to use when ABP (see below) fails. |
| AdBlock Plus | The name says it all. Great extension. |