No 00's or pre-1920's (ie. Classical of various eras)?
As a music grad I'm pretty omnivorous when it comes to music. The bulk of popular music I have is from the 90's/00's but I've got reasonable collections of music from the 1940's-present and then a mix of stuff from before then including jazz/classical/etc.
I like the acid (LSD) type rock of the sixties and early seventies the most, but I listen to all types of music. About the only thing I don't car for is today's rap, I will listen to old school rap like Sugar Hills Gang.
70's, definitely. I grew up listening to Bowie, Queen, Sweet, Whitesnake, Zep, Stones, etc. Best music ever, although I do like other eras (30's for Blues, 50's for Rock & Roll, 60's for varied stuff and the best thing to come out of the 80's was the Sisters of Mercy).