Nice and easy GNU/Linux apps?
Inspired by this blog listing cool Mac apps that I found through digg, I am thinking why wouldn't we make a cool list with descriptions, images and small screenshots of some of the coolest, most useful, intuitive, good looking and *easy to use* free apps that are available for GNU/Linux and easy to install at least on Ubuntu, FC and SuSE as major GNU/Linux distros.
So before I am to compile such a list, I'd like anyone to suggest any such "killer apps" that you may be using.
They don't necessarily have to be very popular. In fact, the list would bear even more value if we'd manage to point out some less known yet awesome apps to use. For example, one app I use for email is sylpheed which is quite awesome email client, but not so well known.