I'm a big fan of UR, it's very diverse, but obviously cannot do everything. Cataloging of DVD's is one of the last few things I do outside of UR.
I can highly recommend
www.whereisit-soft.com, perfect for DVD cataloging, imports from IMDB, scans, thumbnails, basically everything you'd expect ... you can then export to CSV and easily import to UR if you wish.
But it would be nice if this could be done inside of UR easily. We'd need drive scan, attribute that is allowed to have only unique values, attribute with auto-incrementing, thumbnail creation, importing from external data providers, ...