Currently I reckon it's about 50pence for 25gb of DVDs, £3.50 for 25gb of Bluray.
Will blank BDs be halving in price any time soon, if ever?
I can't see myself backing up a 1TB drive to 200-250 DVDs lol, too much work.
I have a 1tb drive backed up to a 1tb drive, but when I want more storage I need a cheaper solution than buying 2x more 1tb drives, discs are also more secure of course.