It's just rock I guess. They have crossed over allittle. Categories aren't that much of a factor anymore.....It's just music. Once upon a time we used to call it middle of the road, but I'm not sure if that's still relevant or not. If you like it then it's good.
I read ages ago on evanescences website they class their music as rock.
Gothic rock/alternative rock
ps FAVORITE BAND!!!!!!!!!!!<3
Some people would call them nu metal but I'd say rock.