Deep Purple, try and get some live stuff much better. Soulfly if you looking for something heavy, I recommend "Primitive" class album. Disturbed are good too you should get the first album though, "The Sickness". And Pitchshifter are good too get Deviant as their first was dodge. If you like Disturbed and Pitchshifter go for On Minuet Silence they are another not too heavy band. Finally some of the really heavy stuff.
Fear Factory, get their old stuff and you'll see what I mean.
Slipknot, By far the best NeMetal band Imo.
The Haunted, either of the two albums are good.
And finally Decide, Heavy metal in tonnage form if you ask me.
Any way you have said that you are into the heavy stuff but give some of the lighter ones ago I quite like um.