Ooo i love intense vocalists. Here's some:
Page Hamilton on Born Annoying (1993), and theres also some gems on Strap It On, like FBLA and Murder.
Jeremy Enigk on LP2.
Bobby Digital on Domestic Violence sounds pretty angry. Very PC.
Drive Like Jehu - If It Kills You.
Eddie Vedder on Leash.
PJ Harvey on pretty much the whole Rid Of Me.
Thirty Ought Six - songs like Dealt, Tike, Eris and Tourmaline (which happens to include Enigk)
The Hated - Words Come Back
Yaphet Kotto - If you can stand the sometimes awkward teenage angst vibe
Beastie Boys - Holy Snappers
Company Flow - Lune TNS
Divine Styler - that jamaican guy on Grand Design
Skinny Puppy - some of their finest moments on: Scrapyard, Circustance, God's Gift (maggot), Human Disease, Bark

Matana Roberts is an emotionally intense one

Lets all just be contrarian and act like Kurt Cobain wasn't one of the best emotive vocalists of all time.

Neil Young on the albums Tonight's the night and On the beach

bukka white
louis armstrong is pretty intense here i feel. and recently i have come to realize how this is simply one of the greatest songs.

http://youtu.be/QzcpUdBw7gs

How about a trio of chix?

Johnette Napolitano - "Joey"
http://www.youtube.com/watch?v=OdpTcvSn8HQ&ob=av2e

PJ Harvey - "The Dancer"
http://www.youtube.com/watch?v=z7o8URBIHLE

Carla Bozulich - "Dragon Lady"
http://www.youtube.com/watch?v=ibJZUXuD16s

There are more emotions than pain and love you know