Since the 60s I think there have been many bands that changed the face of rock or suprised a lot of people.
Which band out of the following do you think had the most impact:
The Beatles
The Who
The Sex Pistols
Black Sabbath
Led Zepplin
Motley Cure
Nirvana
Pat Boone
Although I think Black Sabbath/The Who/Led Zepplin were some of the pioneers of hard rock music, I don't believe they had the impact that Nirvana had. Nirvana pretty much killed the careers of Poison, GNR, and all the other hair metal crap that the late eighties is famous for.
This is just my opinion of course.