Iscariot, the bands your talking about blend a lot of differnt tones. They combiine digital with mic'd sounds. I'm a big fan of all of the bands you mention. I use to be a huge Line 6 guy, but then I discovered Native Instruments Guitar Rig. Their program gets you up and running in no time. The cool thing about Line 6 is that you can go to their website and download user presets. Some people post presets that sound like Black Sabbath, Carcass, Nevermore. Check out http://www.customtone.com/index.html
I think you'll find something you'll like. You'll need to use midi to transfer the tones unless you have a POD with USB. You can also try a technique known as re-amping. The thing that has worked best for me has been to blend different amps and creative panning. Good luck. You'll have to post your stuff so that we can hear what you came up with.