I also notice that a lot of people here are jumping to the defense of System of a Down and I must say I agree. SOAD is the only "nu-metal" band that really stands out in the category. System's songs and lyrics have some cool themes much like early Metallica (no, I'm not saying they sound very much alike but the themes of the songs are similar) unlike the emotionally insecure screaming of Slipknot (they have 4 more members than they need and Cory can't sing for his life), Linkin Park (Chester sounds like he has a vibrator stuck in his larnyx) and of course that poser Fred Durst. SOAD's songs are also quite catchy 99% non-depressing, they'll even make you laugh sometimes. It is for this reason that I find it hard to actually call them nu metal. Maybe Alternative Metal would be better for SOAD. Besides, does their lead singer Serj sound much like your typical screaming nu metal frontman?
Overall, nu metal is like any other musical genre, with good bands and bad ones to match. Good nu metal bands include SOAD, Atreyu, Disturbed, Ill Nino, and some KoRn. Bad ones include poppy bands such as Linkin Park, Slipknot, POD, Limp Bizkit, some KoRn, Puddle of Mudd, and Drowning Pool.
Nu Metal is closely related to rapcore.
Look at the "broken love"/other themes ratio of most genres. For pop, it's 90/10, for example, 80/20 goes for emo, hip-hop has almost no love, but that's another thing. You see, nu-metal DOES have love songs, but they are different from the masses, and the ratio is something like 40/60.
And why should people blame nu-metal for being mainstream-friendly? Why, in fact, is being "mainstream-freindly" bad? The mainstream is what most people currently like, and, even when its fashion goes away, there would people still listening to it.
And, who cares what kind of people are the musicians? Probably most famous classic music composers were mean bastards, but their music is still remembered. The Beatles were dope-heads, but they still are great. Understand it, nobody cares if Fred Durst is a poser. If you like LB, you like it. And if you don't, you don't.
So stop f***ing around and don't forget that music is made for people to have fun, not to argue. K?