Columbus Metropolitan Library rocks! I honestly couldn't imagine homeschooling without this awesome library system. We get to take advantage of a group of connected libraries with perhaps the best selection of books dedicated to providing resources to the community. The website here has a highly searchable catalog that allows you to reserve books online, as well as access to resources such as NoveList, full text of Columbus Dispatch, and Mango Languages.
Presently my absolute favorite feature of the website is the ability to create a username under which you can save booklists and tag books. You can choose to make your lists public or not and view other user's public lists and tags. If you haven't yet, check it out!