Here are a couple of suggestions although I will admit that these are going to be 'tame' in comparison to some of the other stuff listed in this thread.
Soulbender
Led by Queensryche guitarist Michael Wilton, he got this project going to express his darker side. It's great. I've had the CD for a couple of years before they ever had a page on myspace. All of the songs are good IMHO, but check out the anti-intolerance anthem "Samsara". Supposedly a follow up album is due out sometime soon.
http://profile.myspace.com/index.cfm...endid=15304045
Sticking with the Queensryche side project theme I'll introduce you to Slave to the System. You may have actually heard them on the radio recently as they are finally starting to get some airplay three years after the CD was released. The band features Queensryche drummer Scott Rockenfield, former 'Ryche guitarist and producer extraordinaire Kelly Gray and Brother Cane (great underrated band) alums Roman Glick and Damon Johnson. There are 4 songs on their myspace page, good ones. There are at least 2 on the CD that are better than any of them IMHO. Of these 4 I'd reccomend Stigmata first.
http://www.myspace.com/slavettsystem
Finally, while it probably doesn't fall with in the genre of metal at this point, Eagles of Death Metal gets a huge thumbs up from me. Everything Josh Homme touches is freaking brilliant.
http://www.eaglesofdeathmetal.net/index.php?p=audvid
This link has various video versions of a few of their songs.
Of the stuff mentioned in this thread, I really dug A Place of Skulls. I would absolutely adore Opeth if they had no vocals. I simply can't stand the vocals. Outstanding music, but the vocals ruin it for me.