Let's see...
Robert Johnson: Father of the blues
The Beatles: Boy band mania... McCartney and Lennon are still to this day some of the best song writers ever
Chuck Berry: Brought "electric" music to the fore front
Eric Clapton/Yardbirds/Cream: Made "electric" music more popular... molded the "rock" style of Chuck Berry into a more modern sound that came to be known as "Classic rock"
Lynyrd Skynyrd: Created a sound now known as "Souther Rock" which blended classic rock sounds with country music touch... and in a very short time put together one of the best collection of songs by one band ever.
Jimi Hendrix: Changed the way guitar effects were used as well as created a whole new approach to guitar playing.... blending the blues with rock style riffing....
Led Zeppelin: Changed the approach taken to music... Changed the way a lot of bands approached song writing... More of a freeform approach. The sounds of Jimmy Page morphed the way the guitar was played once again...
Black Sabbath: Created what we now know as "metal" music...
Pink Floyd: Dark Side of the Moon.......... That's all I'm going to say.
Ever since Sabbath the changes in music have been subtle..... Most changes not happening in the way music is actually being written or played... but simply what is popular...
Metallica: Takes Sabbath to a whole new level
Iron Maiden: Takes Metal music to a whole new level
Ozzy/Randy Rhodes: Changes the meaning of "Lead guitar"
Eddie Van Halen: In a league with RR.
KISS: Glam...
The Ramones: Don't know much about "punk music" but I'd have to say that they were close to first...
Motley Crue: Cool Glam...
Guns N Roses: The bridge between grunge and glam...
Soundgarden/Nirvana/Pearl Jam/Mudhoney/many many many others that don't get credit: The Seattle bands get dirty.... create a grunge/grinding sound that is taken by storm when "Smells Like Teen Spirit" goes from a cult classic to a mainstray hit overnight.... making grunge music not only cool to the kids with torn jeans and poor family lives.... but also cool to the rich suburban americans and their guess jeans and sweaters.......... The MTV craze erupts..... slowly killing off any chance for low budget music to ever be successful...
Since then not much has changed
New Kids on The Block: A product of MTV.... gave the formula for every boy band of the future..... the embryo of the clones NSync and the Backstreet Boys...
It's hard to come up with any other bands that really CHANGED music in the last decade..... most music has just been variations of the same stuff over and over.... Mainstream music has really stayed the same... That's why bands like 3 Doors Down and Nickleback can keep writing the same song over and over again and still have a multi platiunum album every year.... Because mainstream is mainstream.... and it's hard to change that.... The most change is found in the Indie/Underground scene.... which rarely never sees the light of the mainstream market..... MTV stunted the growth of music... There is no public opinion of what is good music and bad music.... and what changes are widely accepted and rejected..... MTV has force fed the same crappy music to the public for the last decade and a half.....
