Hmmm..., the ones I've listed actually are the ones I really really like listening to, that are straight metal. Also Sepultura, they kinda have that Machine Head groove riffs. They have 3 very popular albums who many people discuss is the best. Beneath The Remains (more straight trash metal), Chaos A.D. (more like Machine Head) and Roots ofcourse. And there is also their album Arise, but I haven't listend to that one yet.
Devin Townsend Project. His albums really varie every time. Ziltoid is very heavy and is just something you'll atleast want to hear from beginning to end, though. It's about Ziltoid The Omniscient, who wants to qonquer the universe and needs a cup of coffee from the earth or he'll destroy it. Townsend is a crazy fucker. Ki is more zen/yoga/relaxed. His music isn't like anything you've heard before, he's also quite humorous.
http://www.youtube.com/watch?v=8eDngElZBxQ
He often also puts the Ziltoid puppet on stage or on video or something.
Fredrik Thordendal's "special defects sol niger within" is cool also if you like Meshuggah. But you really need to be in the mood for it because it is even more hellish/experimental than Meshuggah.
Paradise Losts's Draconian Times album is really good. Kinda like Metallica, but more uhmmm... magical/earthy/medieval, just a bit , though.
Porcupine Tree I like some stuff from. Their album "Fear of a Blank Planet" I used to listen too alot. Also saw them live at that time, great great show. It's kinda like uhmmmm...TOOL, maybe, nah, I dunno.
http://www.youtube.com/watch?v=6bcE_LUxaJY
I seldom listen to other stuff from them, but I dunno why, I'm so lazy.
Nile. I like their "Those Whom The Gods Detest" album. I barely listen to death metal, so I can't really describe it.
I'll post some of my fav "metal" songs later. I'll have to go through quite a big list to find them.