Re

I like to put them through a tube pre and saturate the pre and then compress them to get them to sit in the mix, after all it isn't a very dynamic genre. So compressed and properly mixed is the way I would go, Plus depending on the mic selection you have I would try some nice dynamic mics, I've been using them more and more these days.

Plus if you are looking to do overdub screams, you could always get a green bullet (or like) and then run it hot into a tube pre and compressor and get a nice filtered saturated scream sound. You should check one out, very neat mics, I've tried using them as drum room mics too.

Bob

I feel you will and can get awesome metal tracks, fairly easy. However I was curious how much money you want to throw down?
My vocal tracks used to sound like ass. Then I threw down some cash and WOW!
Glad I did!
I'm saying somewhere around $100-$200 on a mic. (no more)
A decent preamp--- cheap ass ones are exactaly that, so get something that you can afford and that if you want to resell it to get your money back, you will get 80%, maybe more!
Lastly you NEED a effects processor! Mostly for reverb! And I like delay also. We can talk more about cost friendly effects processors. Or if you are going to spend $$$$ there are many awesome ones out there!
I get great results with these 3 things alone (mic, pre, effects)
Peace