Another vote for LibraryThing.com and a barcode reader or smartphone. I scanned in ~1100 books, and only ran into 15-20 without ISBNs. All but 3-4 of those were easily input by title. But I like it because its very easy to keep up, and isn't a moneygrubbing advertising/tracking site like Goodreads. The phone app is very handy when wandering in bookstores-- easy to check if you own such and such a title.