I'm not a big fan of metal myself, since I have some borderline autistic friends, (they're actually quite cool, but when they start talking about metal and listening to this shit nonstop I just wanna shoot myself,) but I have had my fair share of ONS and a lot of them were metal cuties, but I gotta warn you, they almost exclusively listen to metalcore, so if you're really into metal you might want to compromise.
Other chicks I talked to that are into "real metal" were as borderline autistic as my metalhead friends and also kinda filthy.