All you death metal vocalists...

Keep of Kalessin, Thrashy w/ brutal vocals. If you haven't heard them, you need to asap.
 
daz436 said:
scream 1 track, deep growl the other. sounds nice. (eg - the end of wreath)

Yeah. That's a cool trick. When it's pulled off correctly, it sounds sick. One for oomph, the other for clarity. It's kind of like building an explosion sound effect for a movie. Usually, it's comprised of multiple sounds for maximum impact.

I also agree that it shouldn't be an all the time thing. Just like movies shouldn't be all explosions (I'm talking to you Michael Bay and Jerry Bruckheimer...)