Akregator is a fast and light desktop client for browsing and manayour feed subscriptions. It offers all the basic functionality you need from any feed reader: importing / exporting feeds from OPML files, organizing feeds in folders and subfolders, marking posts as important / read / unread, new item notifications, searching in feeds and multi-tab support.
It has an inbuilt browser based on Konqueror (WebKit) for opening links within the application. Akregator can be minimized to the system tray and continue monitoring your feeds and displaying notifications without coming in the way.
It sports three different UIs modes for displaying feeds, one is the standard interface similar to Thunderbird, the second is a widescreen mode where the feed list and article content are shown side-by side, and the third is a "Combined View" which shows a summary of all the posts on a single page.
For a power feed consumer, it might seem light on features. It doesn't support tagging, and has very few sharing options. It is however a very fast and light application, with an easy to use clean interface.