OK. In all seriousness, my personal preference is a tool that would a)let me tag every connection, feed, and post arbitrarily, b)display the most common connections/posts/tags/posts-from-connection-tagged-x easily, c) let me specify tag groupings via drag-and-drop and command-line regex, d) handle all logins without jacking my privacy.
I'll pay you zero dollars for it, but I'll let you show me relevant ads on alternate Thursday. You in?