How do you decide what to read?

I have always been a "book-a-holic". I used to get books every month from the Mystery Book club but I have stopped buying them recently. I have a book shelf in my bedroom with many of those books on it that haven't been read yet. [see my Goodreads ID photo:] I walk down the book shelf when ever I go to Sam's or Safeway to see if there are any new books I can afford and want. There are several authors and series that I just buy the next book in line (although I hope I can find it at a discount). I love browsing at a library book sale. I worked one year for a school book fair company and I got a lot of YA books with my employee discount that year. I borrow books from my quilt club library. I trade and borrow books from my friends. (We had an informal book club called "The Bingo Ladies and Jay" when a club I belonged to was doing bingo every week.) I now work at an airport and all of the gate agents, ramp agents and airline crews usually have books to read on breaks or during slow times during the schedule. They leave books in the break room and sometime passengers even give us books. I subscribe to Ellery Queen and Alfred Hitchcock short story mystery magazines and always have one in my bag for those minutes I may have to wait in a line. When my Mom died, I brought home most of her library including a set, "The World's Popular Classics". My husband is also an avid reader, but often he reads non-fiction that I am not interested in. Once in a while we do read the same books. My younger daughter got me onto Goodreads and we often share books [although this year she is in the Peace Corps in Albania so that is harder right now - I have sent her some books:] And now I am also sharing books with my almost 12-year old granddaughter. I like my Goodreads list because it is helping me keep track of what I am reading, what I have on my shelves and what I would like to read.
So with all that, I just pick a book that I have that tickles my fancy at the time and read it. Sometimes I will go for all the unread books by a particular author and get on a kick. I recently joined the Goodreads group "Pick a Shelf" and that is helping me focus on a theme each month. Basically, I don't usually know what I am going to be reading next and that's half the fun. My friends and family will tell you that I am always reading.