The first Beleza Tropical is a great compilation put out by Luaka Bop (David Byrne) that serves as a nice intro to Brazilian shit.
I don't do a lot of reissues, but Elvis Costello's Trust reissue has a couple of nice bonus tracks.
Double albums? Holy shit, dude. Songs In The Key Of Life, All Things Must Pass, Layla, Tusk, Physical Graffiti, The Wall, London Calling, Exile on Main Street, Blonde On Blonde, Bitches Brew, The White Album, Wu-Tang Forever, Sign O' The Times, Quadrophenia, Measure (I think that counts, but you know me, I'm a Field Music fanboy), At Fillmore East, Rock of Ages (The Band live). Probs missing some obvious ones, too.