Do you have a plan of what you're going to read the rest of the year? Have you had a master plan all along? If so, have you stuck to it? What helps you to decide what you're going to read next? Challenges? Book groups? Or do you have the luxury of closing your eyes and picking any book off your shelf?The second question is talking about spreadsheets and ways of organizing books to be read, but I don't.
Anyway my answer is more or less option three. I do tend to read whatever suits my mood whenever I finish my previous book, but these days, I'm usually picking up books I've been sent for review before I tackle anything on my shelf. Hardcover books usually get the pick over e-books too (and I'm feeling a bit guilty over that, as I have a couple of e-books I've received from the LibraryThing Member Giveaway that I need to read).
There's also a couple of challenges calling my name too: The Arthurian Challenge, the Pre-Printing Press Challenge, and the What's In A Name Challenge. All of them need some reading to be done towards them. Where I can, I'm overlapping books for those (mostly the Pre-Printing Press and the Arthurian Challenge).
I don't spreadsheet my reading, but I do have a document where I list the books I've been sent, where the reviews are to go and when I finally get to them and get the reviews posted. It's nothing fancy, but it does keep my commitments at the front of my mind. There's also the rough list of my TBR pile/Unread Books on my blog.
I choose my reading based on what I feel like. Sometimes I get a real itch to read an old favorite or something, where I can almost see specific passages, or else it will be because I'm in the mood for more like the previous book I read, or I'm on a particular author "kick". The last is what's motivated me recently with Michelle Moran's books. At the moment I'm reading Cleopatra's Daughter and loving it. Not overly certain what's next on the list though. Perhaps A Breath Of Snow and Ashes, as the book following it is due out soon. Not particularly organized perhaps, but fun.