The four walls of the dining room at Roseholme Cottage sport floor-to-ceiling shelving devoted to naught but my roommate's SciFi books, shelved alphabetically. She's posted a picture of the Aaa-Far wall.
I always shelved non-fiction by a rough Tamara Decimal System and shelved fiction by author, but Instead of arranging authors alphabetically, they were ordered by how likely I was to want to grab one of their books to re-read. Thus, Heinlein took up a couple shelves at eye level, while, say, Songs of a Distant Earth, some Jack L. Chalker books, and a Robotech serial novel I'd somehow picked up but never got around to trading in were down by the floor in the back row of a two-book-deep shelf.
(Arthur C. Clarke always annoyed me; someone who just can't wait to be subsumed into the Great Hive Mind and actually sees loss of the individual self as an improvement may be shaped more or less like me, but I would argue that speciation is underway.)