These are my choices.
1) Most important rock/metal band: Led Zeppelin. The most important in
mainstream rock and metal. They have been copied by billions of
rock/hard rock/metal bands till date. They made only 8 albums but 6 of
them were classics. And they lasted only 10 years but made an
everlasting impression on mainstream rock and roll. Responsible for
successfully bring back blues, country, reggae and folk music into rock
and roll
2) Most important pyschedelic/space rock band: Pink Floyd. The greatest
among bands who made experimental electronic based rock music. Their
initial period (Piper to DSOTM) was more creative and shall I say
weird. There were weirder bands out there, but none of them was as
successful as Floyd. It is amazing that with a sound so non-commercial
and negative, they still managed to be that successful. Responsible for
creative a style which is difficult to emulate and also for bringing
synth and processed sounds as a major force into rock and roll.
3) Most important progressive rock band: Yes. Seriously.... which band
can boast a line up of virtuosos like Steve Howe, Rick Wakeman, Chris
Squire and Bill Bruford. All of them would make the top 5 of the list
of the their respective instruments. Well... may be not Steve Howe...
but he is clearly top 20. And they were untouchable as the prog band in
the 70s. No one came close. ELP were probably more talented but their
music had too much of wanking instead of melody or good composition.
King Crimson were more creative... but then they lacked the
consistency. Yes was numero uno in prog... hands down. Responsible for
bringing back classical music into rock and roll and also
keyboards/melletron/organ as a important instrument in rock and roll
and also creating the genre of power ballad rock/power metal (listen to
Drama).
4) Most important alternative/experimental rock band: Velvet
Underground. No band was more influencial than VU. They created a new
style of rock and roll which was opposed to the pop and r&b based style
of Beatles and Rolling Stones. And they were very creative at it. Their
debut album is probably one of the most important rock and roll records
of all time. While they were not extremely talented, they were great
composers. And they were singlehandedly responsible for all forms of
alternative music like punk, new wave and modern atlernative rock.
Responsible for bringing avantgarde and that droning noise music into
rock and roll.
These are my 4 picks... what are yours?