Show the actual list of user feeds in the sidebar, instead of a hardcoded list.
By default folders are closed and no feed is selected in the sidebar.
When clicking on a feed in the sidebar, the feed entries are loaded via Ajax. Also, the refresh button fetches the last clicked feed (that is, the feed currently displayed).

The "read all feeds" link is not working yet. Folders are not implemented yet.
When clicking on a feed in the sidebar, clean the entries list before downloading. Also change the title of the feed list to the title of the clicked feed.

This is less confusing for the user. When clicking on a different feed the loading of the entries can take some time; during this time it's less confusing for the user to see an empty list of entries, instead of the entries of the feed he was reding before.
When clicking on a feed in the sidebar, the feed title and the URL it links to change to those of the clicked feed.
When clicking on a feed in the sidebar, an animaged spinning icon is shown while the entries are loaded via Ajax.
When clicking on a feed in the sidebar, show a "loading..." message while loading via ajax the list of entries.