#1. Extensive liner notes, detailing the history of the album (how/why it was made, etc), it’s historical context and overall impact, details on the musicians, producers, etc. and any other musical minutiae that relates to said album.
#3. Rare and unseen photos.
#4. Creative packaging that nonetheless stays true to the original vinyl LP packaging. A protective outer “faux” sleeve would be nice but not essential.
#5. Perhaps most importantly the album better sound better than my existing copy.
#6. Essential B-sides, demos or an unreleased concert in it’s entirety. I hate single live tracks.I have bought too many “special edition” cd’s with absolute dog-crap B-sides.
Further reading on this subject I am going to send you in the direction of a great article by one of the fine musos over at allmusic.com entitled