check this out, it's a nice guide and includes playable tracks for each sub-genre.
click on the silver skulls to change the genre summaries. i found clicking on the actual text isn't very responsive.
It's pretty good, but it overemphasizes some sub-genre/scenes and doesn't represent a few important ones. For instance, where the fuck is the French black metal scene of today? Every metalhead I know is shitting themselves over Deathspell Omega (and rightly so) and bands like Antaeus and Blut Aus Nord are just as important.
ive only heard Deathspell omegas last album, i like it tho
Paracletus is fucking phenomenal, but everything they've released since 2004 has been pretty much gold.
Si Monumentum Requires, Circumspice  (the first part of the trilogy)
"Mass Grave Aesthetics" (a 20-minute track that first appeared on the split From Entrails to the Dirt... , then later released as a standalone EP in 2008)
Kenose  (the "appendix" to Si Monumentum, basically a mini-album, but it's quite possibly their best release)
"Diabolus Absconditus" (another 20-minute song appearing on the split Crushing the Holy Trinity , hasn't yet been released on its own)
Fas -- Ite, Maledicti, in Ignem Aeturnum  (the second part of the trilogy)
Chaining the Katechon  (another 20-minute track, definitely the best of the three, released as both a split and a standalone EP)
Paracletus  (the last part of the trilogy)