Shelving the past?

Some people are talking about how they organize their books. I posted about this some time ago, but my book collection has been moved, reorganized, and enlarged since then.

I have exiled the law books to the living room, kept the Ayn Rand and free books in the second row, and largely maintained my lit-fic/trashy SF/fantasy divide. But I acquired a fair number of battered paperbacks from the Book Thing last summer; some of them even made it to Clerksville. My frequent air travel has necessitated the purchase of several underwhelming books which currently lie dejectedly on the forepart of the shelves, waiting for someone to purchase them off Half.com. I even received some books as gifts (for example, this one, an odd epistolary fantasy currently being made into a film starring Hugh Jackman, Christian Bale, and Scarlett Johansson's bosoms).

I'm currently debating whether or not my shelfworthiness strategy, which almost always involves purchasing books after I have read them, should be modified to accommodate the needs of a more harried lifestyle. Constantly renewing library books because I forgot to bring them on court week may be more of a pain than sucking it up and paying six bucks for my own copy of Moby-Dick.