Having gotten fed up of Google Reader's cluttered and tired looking interface, I decided to mockup what I would want in a feed reader if I created one.
As you can see the main focus was not to distract from the new items. Below the main screen you can see headers for alternative themes that could be used, I wouldn't restrict users to just the minimalistic grey theme.
Then to the right you have the Add Subscription modal dialog, just keeping everything very simple. Finally you have the Preferences.
Just a note, I am not planning to create this ... yet...
Icons used are from elementary icons and the mario images are from [link]