He sounds ESFP in stage banter and interviews, but that could easily be an act.
Still, his trademark disheveled appearance could be just that--his trademark look. SPs tend to have their own unique sense of style; that might be Grohl's take on what a rock star should look like, and not just due to N-obliviousness to the physical world.
So I'm going with ESFP, but I'm only moderately sure.
If you could be anything you want, I bet you'd be disappointed--am I right?