I wrote a reply to this and then somehow deleted it. A summary of sorts: I read the first six pages of Black Sun on Amazon (the library will have to wait until Tuesday) and I can't help but think that the "abyss" of which Kristeva writes is fundamentally out-of-step with Melancholy Now. Isn't melancholy a positive thing these days? Sure, it contains sadness, but only as a tincture to innoculate against the original. Current instances of melancholy in literature, music, film = trying to be happy at all costs, in the face of ... (for Benjamin, the future was mind-bogglingly more horrific than any of us today could ever contemplate -- for Benjamin, the end of everything actually had a fucking face*).
As an example of the shift in melancholy, how many people think Talk Talk's Spirit of Eden is a genuinely depressive album? Only people on very speedy drugs. (Hockey players, also.) Would Kristeva (bearing in mind my six page understanding) think the same thing about it?
* -- I think we're all giving Chimpface W. Bush too much credit. He couldn't putsch his way out of a wet paper beer hall.