If you're (still) a Smashing Pumpkins fan, you can't go past the "B-Sides and Rarities" album that has been set up on iTunes. For AUS$17.95 you get well over 100 tracks showcasing b-sides from the band's entire pre-Zwan career. An unbelievable bargain, even discounting for the fact the songs are in a compressed format. A vaguely educated glance seems to indicate it's close to everything they've ever put out that isn't on an album including the Peel Sessions EP, the Batman Beginning Is The End single, b-sides and soundtrack songs.
The fact this exists says a lot about how Billy feels about those tracks.