Re: Good pickup for Metal?
the invader definitely wouldn't be a bad choice. it's got crazy high output, and the focus of the sound is more towards the low mids, so it's fat and chunky without getting into a woofy, indistinct low end. the duncan distortion is also a great choice, though in terms of tone it's almost in direct opposition to the invader; it's focused more on the high-end, but not in a shrill or thin way. it's got a lot more scream, and is very lively in terms of harmonics.
if you're not completely set on duncans, dimarzio has a few humbuckers that would also suit you very well. the super 3 is an awesome choice, and you'll find it near the duncan distortion output-wise but a bit more musical to my ears. the super 3 has a really interesting mid-range that, through a very high-gain amp, gives you a lot of punch and depth. the x2n is a killer, and if you're interested in doing metal and metal only (i.e. you won't really find yourself rolling back the volume for clean-ish tones) you'd be hard-pressed to find a pickup that'll give you more metal than the x2n.