What the hell... You are going to hate this but I like this band a lot and I'm absolutely in love with the lead singer's voice.

So here goes:
Growling
[youtube]8UR_2KqO0aQ[/youtube]
Clean
[youtube]RziLU_-KDE0[/youtube]

i do hate you for it, because you did it twice...

Stolen Babies
a pretty cool Experimental rock/metal band with a great female singer!

[youtube]5GcZHxXTW90[/youtube]

MIA is pretty great if youre into hip-hop.

Otherwise, you cant really go wrong with Heart, Azure Ray, Yeah Yeah Yeahs, or Blonde Redhead

Nebelhexë
Unter Null
Gallhammer

billie holiday

Billie Holiday should be one of the first ones he/she gets

Good call.