With the demise of Google Reader, Feedly is my RSS feed reader of choice. It's essential for anyone looking to keep up to date with their favorite websites.
The Chrome app is a wrapper for cloud.feedly.com, but having it installed means there's an icon to click on the dock, which can be set to start full-screen rather than in a tab.
I use it to track the news I post to Twitter, research for my InfoWorld column, and so on. It's able to clip text to Evernote as well as keep track of what I have read across all the places I log in to Feedly.
Unfortunately, it does not offer an offline mode for reading while traveling; otherwise it's near perfect.