Erm... Don't delete anything at all
?
Nah, to be honest, I'm not sure of thesituation and how bad it would be... WoW could always be reinstalled, anime music can be taken from Gendou... Most episodes shouldn't be too hard to get... A few Hentai Doujins could still be taken from Fakku.net.
(Though my recent Nanoha SEED collection would be painfully missed, and not to mention those from blood aren't be replaced...)
So the really heartache would be losing my 800-1000 random and known anime related images...