I'm not necessarily a Skrillex fan but I am a Korn fan and they did this song featuring Skrillex. In fact I think there's a couple on their new album, which I'm yet to buy.
I like the forgotten by killswitch and there's a song called 'a boy brushed in red living in black and white' think that's an underoath song, they're pretty much the heaviest bands I listen too lol