Well i have a personal collection and a bigger 'family' collection that I've inherited. In the personal is the ones I've actually read, as a reading book, not research...although most of them are research. I've philosophy ones, fantasy ones (probably the biggest), history of design, graphic design, industrial design, theory of design, Greatest Portuguese literature (romance and poetry), old classics (included in philosophy), etc. In my bigger one, i have 2 most common genders, Art and Philosophy. Oh yeah, that's why I'm weird.
So my personal one has fantasy books (Harry Potter, Lord of the Rings, Portuguese lord or the rings style, Eragon too, JĂșlio Verne, etc.)
oh, my personal collection has HUGE collection of comics, Corto Maltese (Hugo Pratt is my favorite drawer/style), Tintin, what you call Smurfs, we call Estrumpfes, Asterix, and other European comics.
When i go to a library, I'm normally looking for a specific book, but i can wander around a library trying to find an expensive Taschen or something like that, normally directed to Design.
The best book I've bought like that (not sure if it's Taschen), was a HUGE book about Hokusai, his whole life and art.
I normally hear about a book from friends or TV or radio, and then i go check if it's fine, my mom does that work for me, buys allot of books and i read half or a third or less of what she reads.
I don't like to read sci-fi at some point, unless the whole point of the story isn't being sci-fi...allot of sci-fi books only focus on being in outer space and weird technical stuff and things like that. I rather movies for that...if it's more complex, fine. (I mean, a large number maybe even majority of sci-fi aren't complex in my opinion)