NewsRack is a powerful RSS reader for Mac OS X that can be fully synchronized with your Google Reader account, including the ability to edit your feed list from within the app.
It offers a keyboard-friendly, tabbed interface that stays out of your way, so that you can focus on the news and blogs you care about.
NewsRack is also available for iOS.
Not just your unread articles, you can also add feeds, change their titles or rearrange them in categories, all without leaving the app.
The tabbed browser allows you to read linked websites without leaving the app. You can also use tabs to keep an eye on multiple feeds.