On my quest for good music (with the help of my good friend) I have found such great bands as Linkin Park, Silverstein, Disturbed, Atreyu, In Flames, As I Lay Dying, Machine Head and Soilwork. And to a lesser Extent Nickleback and Metallica.
I don't know, when I was into Disturbed and Machine Head I was also big into Godsmack? Maybe you should try a bit of their stuff, although a lot of it really sounds the same.
I can honestly say that Opeth is really good. I especially like the album 'Blackwater Park'. This is the first album I listened to that has Cookie Monster vocals (a term you may or may not have heard before about the roaring/grunting type vocals) and actually liked. If you're anything like me, listening to this album might take a while getting used to the vocals, but it will really broaden your horizons afterwards.
Let's see. Have you listened to any Orgy? Most people with your taste generally dig the first two albums by this band. People are really conflicted about the third, though (personally, I hated it with a passion).
Then there's also Soil (not Soilwork) which is also pretty good. I would consider this band to be halfway between Disturbed and Saliva. The songs 'Halo' and 'Breaking Me Down' are generally well received among nu-metal fans.
For the Linkin Park fan I would suggest you try and find a couple of songs by a band called 'Dry Cell'. They are Linkin Park except without the rap and with a 'harder' edge similar to Disturbed. They managed to crank out a couple of catchy riffs in their short time too.
Also, whoever suggested Pantera is completely right. Pantera is quite a bit heavier than Disturbed, but it is definately on of Disturbed's biggest influences.
If you like Nickelback and post-thrash Metallica (which is to say when they started doing songs like Enter Sandman and Hero Of The Day) you would probably like some grunge and post-grunge. I recommend Alice In Chains and Soundgarden for the actual grunge, and for post-grunge I have to say Default and Alter Bridge (Creed sans annoying singer) are pretty okay.
Last but not least, I'd like to recommend Finntroll. At first you'll be appalled, then you'll laugh at it, then you'll start listening to it because it's amusing, and eventually the songs will get stuck in your head and you'll actually like them. Happens every time.
Take care now. Make sure to broaden your musical horizon at your own speed. Although if you have the time I suggest you look up some older bands like Black Sabbath and Led Zeppelin.
Also, you might want to take note of the fact that how 'heavy' something is is not neccesarily the same as how 'loud' something is. Disturbed isn't all that heavy, but they are damned loud.
