Innovative bands of the past 25 years

Iron Maiden
Dream Theater
Emperor
Opeth
Metallica
Godflesh
Fear Factory
Napalm Death
Suffocation
At The Gates

Those bands each spawned their own styles of music, if you like it or not.
 
Suffocation really didn't...Opeth just strung together a bunch of stuff that's pretty much all already been done. Metallica were still quite rock based, not that innovative. Maiden didn't do a lot that Priest didn't already do.