Thanks to a link from Rob Hardy's excellent blog, Rough Draft, I've discovered Library Thing. It's a highly addictive web-based service that lets you quickly select and enter books that you own, often in the exact edition you own, and often with cover art. From there you can rate, tag and review your books, find others who share your literary tastes, and create fun blog widgets (see my sidebar, near the bottom of the page, which generates a random list of four books at a time from my library).
I've been startled to discover just how many editions there are of many books -- sometimes dozens. Sometimes I've been able to find mine and sometimes not; you can upload your own cover image and I've done that in a few cases. The default search engines are Amazon and the Library of Congress, but you can access many others, like university libraries, for specialized titles.
Many of my books are in boxes these days, and I'm not going to begin to try to list all the paperback mysteries I own. The books I've entered so far are among my favorites, which is why they are out and accessible, and also why I've rated almost all of them highly.
It occurs to me that I've been building up to this blog for a long time in how I've organized my books. For the past six years, at least, I've had a special bookcase that holds all my books on gardening, cooking, birds, other nature guides, and most of my memoirs (I particularly collect travel and gardening memoir). I've slowly realized that that is the place of honor for any new book of mine.
Anyway, many of those favorite books, and quite a few more, are now in my catalog at Library Thing.