Reuters/Billboard have published an article (Digital album packaging) about making CDs more attractive and encouraging people to buy legitimate downloads. The article suggests that bundling extras such as electronic versions of liner notes, lyrics etc will draw people away from P2P based illegal downloads which only have scanned copies of such material. To think that this alone will lure more people to legitimate purchases is perhaps a touch naive.
Additional material, particularly videos, documentaries, interviews etc can be attractive, but typically these get used to create ‘special editions’ with a huge premium attached to the price which usually puts me off. In addition to this the image quality of these additional extras has been very variable in the past which wont help either.