Written in Java, RSSOwl is a feature-rich reader with support for RSS, RDF and Atom feeds. It has plenty of configuration options as well as a tutorial for getting started, support for tabs, add-ons, labels, Internet services sharing, searching or sorting, pre-defined list of feeds, importing and exporting feeds functions. All in all, probably the most complete application for news reading.

QuiteRSS is one of the best feed readers out there. Written using Qt, comes with a beautiful, themeable interface, it's fast and provides all the necessary features to be a full-fledged news reader.

Liferea is a powerful, feature-complete news reader with lots of configuration options and functions. It has three view modes: normal (with three widgets), wide (three vertical widgets) and combined (two widgets) and it also supports plugins.

This is the default RSS reader in KDE, providing basic functionality, browser tab support, system tray integration, configuration of news fetching interval and three different view modes.

Blam is a GTK-based news reader, with a simple interface (three widgets: one for the list of feeds, the other for the topics in each feed and the third one for viewing the selected feed), support for exporting and importing to and from OPML files, system tray integration.

The RSSNow widget for KDE Plasma provides a simple, list-like feeds from sources which you can drag and drop. It comes with configuration options to change the news update interval and animations.

OK, Inoreader is not an application, but rather an online feed reader. I had to include it here since it comes with some wonderful features, a simple way to add or import feeds, a clean interface, and a bunch of categories to choose from if you don't know where to start. To start up with it, point your browser at https://www.inoreader.com/, and create an account.

Feedly is another web-based reader which allows you to import feeds created by other readers in OPML format. To login, you can use one of your Google, Facebook, Twitter, Windows Live or EverNote accounts.