I used to be obsessed with the Beatles, Beach Boys, and stuff like that. I still appreciate oldies and listen to lots of classic rock/original rock music on occasions but my bro got me into metal.
There's a good 6 or so days of metal music of various kinds in my library, not gonna list 'em all, but I have some policies on metal.
I like a good melody, or at least good skillful instrumentals. I'm okay with screaming, in fact, it's metal so there's a lot of screaming but I can't stand when it's all super low and gravely, or super high all the time. Ranging screams or stylized screams are good. I usually like the combo of screaming verse, singing chorus.
As for actual bands, I'll listen to anything that sounds good to me.