Vocals
I'm not totally sure what you mean by "hard, edgy, biting, slightly distorted vocals", but I'm guessing you want them kind of hot, and you maybe want an 'authentic', vaguely lo-fi recording. Am I right?
If so, there's a very simple - and some would say insane - method (I've used it before to good effect, so it's not total suicide): slum it. Just let your vocal recording peak. It might be a good idea to get pretty close to the mic, as well.
On the subject of mics, what are you using? It would be harder to achieve the effect you're looking for with, say, a condensor mic, because that would involve a lot more processing and production. Use something with slightly less fidelity. I'd recommend an SM58 - I don't have one myself, but I used to use them when I was at music college, and one characteristic that I distinctly remember about them was the hot sound you got from them when you whacked the level up.
If you don't want to go downtown, though, try heavy compression: turn the threshold down and the ratio up, but not so much that you flatten the life out of your vocal. Experiment also with the make-up gain - that should help you achieve the desired effect. It works along the same principle as above, but it's a little more 'scientific'.
