If not an online catalog, do you use any other method to catalog your book collection? Excel spreadsheets, index cards, a notebook, anything?I used to use Bibliophil, but I haven't updated it in a long time, and we have Delicious Library on our Mac to catalogue our whole collection, although some of my recent acquisitions haven't made it in yet. Checking out Library Thing is on my list of things to do someday, but it is admittedly not very high on the priority list. I use a spreadsheet for some of my challenges, such as Reading Across Borders and Book Awards. But I found a fun little notebook two years back that I have been using to keep track of all the books I read and my TBR list.