System of a Down: Novelty band or lasting influence on music?

I am a fan, but personally can't make up my mind... I really really enjoy their last 2 albums, although Toxicity is also cool... So, ping phase or an influential band in the big picture? Bare in mind, Britney Spears and all the boybands will also go down in history, but they didn't really contribute to music as such. Am i making any sense? No, didn't think so... :)