I no longer maintain a "read/not read" column. I find myself more and more wanting to re-read books, especially as new books in favourite series come out. I can't imagine starting in on the new Foreigner book, for example, without re-reading at least the last most recent, and maybe the one before that. Too much going on and I lose track of all that has happened. Which reminds me, I need to leave time to do that before the new one gets here this spring.
What I do maintain is a ToBeRead collection that includes books I definitely want to read in the "near" future. Though I admit, some books have been on there for rather longer than I'd care to admit.