I have a fairly large library, currently standing at 700+ books. The subjects and authors vary, but if looking at someone's library tells you what you need to know about that person, I think most people would run from my house in terror!
There's a whole shelf on serial killers, another on true crime, almost a full bookcase on witches and witchcraft through the ages, then there's the classics, the modern literature, the reference books, a couple of chicklits for when I want a nice easy read, and other miscellaneous books. I never download, I prefer the feel and smell of an old book to anything electronic.
As someone said, a good book is like old friend I want to revisit, the others go to the charity shop.