As much as I like ICP, I agree with AC.
ICP is anything but influential. The only reason ICP has accrued so much success and achieved their notoriety is ecause of their strictly underground style that nobody is willing to imitate, save other artists on the Psychopathic label, and the countless Juggalos that adore their music. I guarantee that if you were to compare a Juggalo and your everday fan of mainstream rap, their views of influential rappers would be polar opposite.
Just because other rappers like Snoop Dogg and Ol' Dirty B@stard have appeared on ICP albums, doesn't make ICP influential.
Let's not turn this into an ICP discussion, please.