I look like a girlie girl (blonde hair, cute clothes, etc) and listen to mostly metal (Pestilence, Gojira, Watain... not stuff like Children of bodom). I'm not sure if guys would find that cool or just weird/stupid since you wouldn't think I'm into stuff like that just by looking at me.
I'm kind of a metal guy; I listen to a lot of the music, and have played it a number of times for different bands, but I don't wear the crazy get-up like the chains/piercings, heavy make-up and the like.
For me, I would like the fact that I can relate to her on some sort of musical level, as music is a pretty large part of my life.
Plus, if she head-bangs, there's an added bad-ass factor as well!
yes, I even have a crush on a girlie girl that doesn't listen to metal and I do all the time (just bought 18 new metal cd's as well). Don't worry about it, you'll find someone, it doesn't really matter how you look, just be yourself :)
You should listen to more Bodom, you'd be surprised by how amazing most of their stuff is. If I had heard it a few years ago I would have been reluctant too, but farrrrkkkk. Their compositions are surreal.
Sorry, this was completely useless for your question, lol. I guess it depends on the guy, but I don't think most really give a crap about what music girls listen to (if they did, most would be sorely disappointed).