Yeah, see my problem with a lot of metal bands like the ones you listed, is the singing is in my opinion something they dont seem to put much time and effort into, its a lot of weird pitch screeming, and low grunts and stuff. Iron Maiden is all right though, not exactly what im lookin for but, its much easier to listen to than most other stuff.
The problem is im listening to a lot of this stuff at work, through a friend whos HUGE into metal, so he just plays a lot of differant stuff, and I cant allways ask what band it is. To be honest, as I go through some of Valient Thorr's and Cauldron's music on YouTube, I dont enjoy all of it either, haha.
Im trying to find more of the higher pitched, less grunty, or screemy, just a more traditional type of song, with fuckin rad metal guitar/drums going on. More Thrash metal from what I've heard I guess.
Edit: and Rage against is awesome, System of a Down is ok, they just seem to go all over the place sometimes.