In no order these are some of the best metal bands out there:

Audiovent
Sepultura < killer shit
Down
Mr. Bungle < wicked
36 Crazyfists
early: White Zombie
tool
system of a down < u got to love them
static X
Jerk
Mudvayne
Breaking Benjamin
coal chamber
kittie < meow
Killswitch Engage
MDFMK
Ministry < old school hard core metal
Soulfly < eye 4 an eye
Slipknot
slayer
Primus < les is God
Produkt
Mindless Self Indulgence < love them
Nonpoint
Otep
Pantera