Recommend me a metal band?

[Hem]

I'd have to disagree with Flyleaf. ^ I, personally, wouldn't consider them metal in any way, shape or form.

Suggested by my iPod (though I know many of you may disagree with me):

Amon Amarth (I don't know how to classify them)
Apocalyptica (symphonic metal)
Arch Enemy (dunno classification)
Dimmu Borgir (I don't know how to classify them either)
Eluveitie (folk metal)
Ensiferum (viking/folk metal)
Epica (symphonic metal)
Kamelot (symphonic metal)
Korpiklaani (viking/folk metal)
Lamb of God (apparently they're a Christian metal band?)
Slipknot (nu metal)
Stone Sour (..possibly?)
Trivium (nu metal)
Winds of Plague (don't know how to classify them)

And then of course there are those who have already proven themselves:

Iron Maiden
Judas Priest
Megadeth
Metallica
Slayer

A friend and I recently had a debate as to what the definition of "true metal" was. I myself am a fan of Bullet For My Valentine, but can see why metalcore could be considered "the enemy of true metal," as he so kindly put it. We got into comparing lyrics, sound, stage presence....

but my brain can only function so late into the night and we never reached a conclusion.