I recently uploaded a large FreeMind map that I collected over 2008, in an effort to get a handle on the stream of security articles, reports and incidents taking place back then. In short there was a torrent and it remains much the same today. I think you might find the ad hoc classification of material useful, as well as the groups of sources.
Note that links to items from FIRST (Forum of Incident Response and Security Teams) are now broken since their once excellent news service has been discontinued.
All sources for my security and risk FreeMind maps are available here.