I have a lot of patterns on the PC, a lot on disc, some on a external hard drive, a lot printed out and quite a few books, i try to categorize the patterns but my filing systems not great, when i scan a pattern from a book i always do an extra one and file it so i can scan that one next time to reduce the strain on the spine of the book, every so often i back up all the patterns on my PC and external drive to CD or DVD, i can rarely find what i'm looking for very quickly but going through a load of patterns isn't such a bad thing as i often find patterns i had forgotten about and i get ideas from looking at the patterns, works for me anyway...
Ian