These are a few of my favorites...

and they may take a while to all load.  :)

Dark Tranquility

Maynard of Tool and A Perfect Circle

Max Cavalara of Soulfly

Sinergy

Children of Bodom

Kimberley Goss of Sinergy

Dream Evil

Hypocrisy

Opeth

Nevermore

Killswitch Engage

Alexi -Children of Bodom

Nightwish

=w=eezer

Angela of Arch Enemy

Ozzy Osbourne

Soulfly

MESHUGGAH

Arch Enemy

Mudvayne

s L A y E r

Testament

Nightwish

Iced Earth + Blind Guardian = Demons and Wizards

Blind Guardian

Tarja of Nightwish

Iced Earth with Barlow

Angela of Arch Enemy