Hmm...well, I'll jump in and try to put my thoughts into words
I remember being allowed to play my parents' records when I was about 8 years old (1970) and enjoyed equally Country and Western (as it was called then) and Rock and Roll.
Yep, Conway Twitty, Merle Haggard, Johnny Cash, The Doors, Cream, The Beatles and so on. Later on I shifted more towards Rock in all of its various incarnations but with emphasis on the harder stuff.
Oldies radio wasn't as popular then as it is now, but I do recall hearing Fifties Rock and Roll. I knew then that it was "old stuff" but I liked the majority of it.
My grandparents would watch The Lawrence Welk Show, that was probably the only music that I didn't care for.
As for the differences in the generations, I remember listening to my new Kiss album and my dad walking into my room and asking "how can you listen to that crap?" If I hear certain genres today, I think "how can they listen to that unmusical crap?"
I'm thinking that when my generation is in the old folks' home, we'll be head-bangin' away (maybe not energetically, but earnestly) instead of chillin' to the strains of Lawrence Welk.