I have no formal list. That way, I can't feel guilty/disappointed about letting it get completely out of hand.
I'm currently reading Sharps
by K. J. Parker.
I have a handful I'm considering reading next. One of that handful will get purchased and read based on whatever whim happens to grab me when I finish the Parker book (I'm currently leaning toward David Brin's Existence
), and the rest will either find their way back "on deck" again at some later point, or will be forgotten for years (or even forever). I never plan on being "done" reading (or even making measurable progress) so a formal list just doesn't work for me. Winging it feels entirely right.