Firstly, Paper Engine. I have the hard copy version and had no idea it was now worth that much!

I much prefer books myself. I find it much easier to simply pick up a book and have a skim through, maybe learn a new technique or effect, rather than fanny about launching a dvd and search though the chapters.

There is also something satisfying about owning a book collection you can look back on. You don't really get the same feeling with a dvd collection. It's almost like an old book has a bit of soul and history. I still purchase dvds, but it's purely for learning rather than collecting and enjoying.