There is no end to the different genre name's out there (within metal). What's metal to one 'metalhead; isn't always metal to another 'metalhead'. For example it might be more like Hard Rock

.
OK well, I'll bite, I like gutteral brutal vocals, but it has to be done tastefully

. Some vocalists are good at it, most vocalists are not so good at it (I'm only referring to all of the 'gutteral vocalists). With this kind of music, it isn't about lyrics obviously, but what sounds good (insert sarcasm here) with the accompanying instruments. In most cases the mood is not neccesarily a happy one, so why should the vocalist sound happy?

Darkness, evil, gloom and doom, all of that good stuff.
By no means do I exclusively listen to gutteral stuff. Phil Anselmo comes to mind as far as great metal vocalists are concerned. He gives that in your face raspy, aggressive till your nuts explode delivery that is required for a band like Pantera.
Other big names that come to mind (Hetfield, Mustaine, Halford and some guy named Ozzy

)
All of the above are personal viewpoints, so don't get offended eh!