Amon Amarth Metallica Lamb of God Disturbed Slipknot Alestorm Five Finger Death Punch Avenged Sevenfold Dethklok Killswitch Engage Rammstein War of Ages
If you're looking for a great metal band, Dark Tranquillity is probably my favorite. Entire discography is amazing (Projector is a bit light, but still great music. Start with The Gallery and Damage Done if you want to see them at their best IMO.) Few of my favorite tracks are: Lethe, Monochromatic Stains, A Bolt of Blazing Gold, Insanity's Crescendo.
A few other gems: In Flames Five Finger Death Punch Darkest Hour (just starting to explore this one, but seems very promising after listening through 2 albums for the past week) Kalmah At the Gates
And a few bands on the obscure side that are definitely worth checking out: TesseracT (Debut album released a few months ago, worth every penny) Vildjharta (Just signed with Century Media, Debut album on the way) Times of Grace (Debut album was exceptional. If you like KsE check them out) Solution .45 Return from Exile