There's sort of a system. I have "incoming" books, which I gotten through various methods but haven't yet read. Some of these I've purchased, some I've gotten from bookins.com, some are from my mom, who reads all the freaking time. Then there are the "outbound" books, which are anything from old novels, to textbooks, to stuff that's come in from bookins and is listed to go back out again. Some of these are listed on half.com, some on bookins, and they are all sitting in boxes in my living room.
On the two massive Ikea bookshelves are what I call "the permanent collection". In what is generously referred to as the "dining room" in my apartment is fiction, and non-fiction that doesn't relate to computers. Here I have stuff from my favorite authors, things I re-read from time to time, and some series like Stephen King's Gunslinger. Also Calvin & Hobbes, Sandman, important stuff like that. There's also some wine, my martini set, the box my camera came in...
In the spare bedroom is the "technical library", my out of control collection of technical books. I've culled this herd several times over the years, and I don't buy many tech books anymore since I have a Safari subscription. But every now and then something makes its way home with me.
In my bedroom are about two dozen books that i'm in various phases of pretending to read. They're fairly well contained in a bookshelf, thankfully.
Then, there is the METRIC TON of stuff for my current classes. Right now, I'm not entirely certain how many classes I'm taking. I have books for a statistics class, a management class, accounting, operations and supply chain, and business writing. Additionally, there are two personal-development packets that go with the management class, and binders for business strategy, accounting, management, and the stats class. I don't know what to do with all of this yet. Sure, there's probably room on my bookshelves for it, but i'd have to move my wine. Or candles. Or the various rabbit and penguin knicknacks that i receive all the time from my mom.
So, right now there is a leaning tower of MBA materials on the sofa table. Beside a foot-high stack of unread magazines. Which is beside a pile of additional office supplies and notepads for school.
I bet I could do a PhD thesis of the impact of having a lot of unorganized books on the psyche of the borderline OCD 21st century woman. And no, I don't burn the candles while they're on the bookshelf. That's just where the stash lives.