I'm on Goodreads as well, only took me about 30 minutes to enter close to 400 books.
It's free, I like the way it works and looks, and I semi-forced some friends to sign up as well so I'm kinda using the social aspect of it.
I really like how you can compare taste in books with others there.
Have a few 'foreign language' - or well, non-English, since for me English is a foreign language
) - books in there as well, no problem finding them in their database.