Here is my classification system. I created it using Inspiration then posted it to Google Docs. Please let me know if it is not showing up for you. I wasn't quite sure how to post it publically!
I especially like your branches off the Instructional sites and Learning sites classes. I would be curious to see your sub-categories for the professional development categories...
http://docs.google.com/fileview?id=0B2uybUDta9tyMGVjMjA5NGEtY2VmMi00Y2U2LTk0MDItOWQzODVkMGJlNzhl&hl=en