I agree that the one size fits all method doesn't really work for everyone on social news sites. My site, http://www.klipboardz.com, tries to solve this problem by using some of the same suggestions that you listed. We have a recommended area that lists stories based on what sites you visit and your up and down votes. We also promote users to create groups and add friends so that they can have as many focused groups as they want to share certain stories. I've found the best way to sort through all the info is to use the group view, which lists the top stories in each of your groups on one page. That view almost always allows me to find interesting content.
Here's my attempt at better social news: http://groups.google.com/group/forwarding-tree. You can try a fully functional service that works like this here: http://forwardingtree.com/
Interesting stuff. I've some similar ideas on how this should be done.