I am sad to say that Google Reader is dead. Feedly hopes to be the tool you transition to. It provides a productive way to organize, read and share the content of your favorite feeds, blogs and news sites. Feedly offers a seamless transition from Google Reader.
Here is a screenshot of the extension up and running:
As you can see it has a really nice and clean interface to read your RSS feeds in. If you are looking for a new RSS reader, Feedly might be your best choice. You can pick up Feedly from the Firefox Add-ons website.