It's never been about any one band or musician, but about records.
 
A record is a quantum blast of energy, an explosion resulting from an accumulation of years of quiet chemical reactions.
 
You might start out unaware that all those pop songs on the radio were being created by jazz and classical musicians, until one day they're set loose. Then you get an album like In the Court of the Crimson King that blends rock, jazz, classical and poetry like some musical Unified Field Theory and suddenly you're the Star Child in 2001 A Space Odyssey, seeing the universe as it really is.
 
Records also provide a handy chronological benchmark. I can think of 5 that were the biggest milestones for my musical journey:
 
1. Hearing the 1812 Overture for the first time as a very young child. I played that record until it was worn out. It was a launchpad for what would become a lifelong love of classical music. And, I suspect, a later respect for metal.
 
2. The Beatles and other British-invasion bands such as The Animals and The Zombies. A love of Brit-pop led me, strangely enough, to American bands who embraced a similar vocabulary. Magical Mystery Tour was the first record I ever heard in stereo. It was what made me realize that all music is connected in an evolving continuum.
 
3. One defining milestone was when our drummer showed up at the band house with a copy of "Are You Experienced?". We immediately set about learning every cut on that album, discovering in the process that rules were just starting points.
 
4. Dave Brubeck's Out of Time album, and its less-successful follow-up Time Further Out, brought jazz to the foreground and taught me that it doesn't have to be in 4/4 to make your foot tap. It led me to seek out Brubeck's contemporaries as well as earlier players who influenced him. I am primarily a piano player because of people like Brubeck, Art Tatum and Bill Evans.
 
5. In the Court of the Crimson King. An epiphany unto itself: rock, pop, jazz - all just labels for the convenience of organizing the bins at the record store. The first ELP album, around the same time, was a similar fusion of genres that further reinforced the notion that musical genres are made-up BS.
 
[EDIT]
6. Snowflakes are Dancing by Isao Tomita. Showed me that synthesizers could be as beautiful as a classical orchestra, more than just ultimately-boring novelties. 
 

For Daryk it's probably The Monkees.

I would say that the one that would leave the deepest hole if NOT there would be the Beatles.

Will be Miles for me too. My brother is named after him, and it was the soundtrack to my youth in our house. Although my dad tastes were broad, it was Miles's side if Jazz that suited my ear than say Parker, Coltrane, Ornette Coleman.

Has to be Frank Zappa for me - been listening to him since I was 3 years old and he definitely tuned my ear to more colorful rhythms and harmonies, and taught me that the last thing you want to do as an artist is take art seriously.

bitflipper
...
5. In the Court of the Crimson King. An epiphany unto itself: rock, pop, jazz - all just labels for the convenience of organizing the bins at the record store. The first ELP album, around the same time, was a similar fusion of genres that further reinforced the notion that musical genres are made-up BS.
... 

There's another blast from the past. LOVE that album. I can still remember the first time I heard it. I was driving an old Dodge with push-button transmission from Devil's Head ski area back down to Madison, WI. 4 friends were passed out/sleeping. The car had only AM radio, but at night, it could pick up the clear channels. I don't recall the call letters of the station in Little Rock, but from midnight to 5 am, they switched from country/trucker music to, well, the DJ played COTCK straight through, both sides. I couldn't wake anybody else up, and it was on a crappy mono AM speaker, but, holy crapola, did that make an impression!

I would say Brahms.  I studied jazz forever (with Barry Galbraith no less) but jazzers are way t()o uptight unless they're addicted to drugs...then, of course fabu.

I really do not want to kname just one of each, but I will.
 
Band: The BEATLES: my age and their popularity
Artist: Neil Young: my rebellious years and similarity of our voices and playing style. I covered a lot of his music from Harvest and CNSY era.
 
I will add that in my years of formal training is was probably Brahams folk songs more than anything else, a little Norman Dello Joio too.. and Bach but mostly Brahams.
 
These days I rarely (almost never) listen to Young or the BEATLES anymore. As I grew older The BEATLES became pretty much offensive to me and Young seems a hypocrite... the music is still good though.
 
Others... there are some, for sure. Maybe I'll name some later with permission.
 
J

@ Bit.... 3. One defining milestone was when our drummer showed up at the band house with a copy of "Are You Experienced?". We immediately set about learning every cut on that album, discovering in the process that rules were just starting points.
DUDE!!! I can play a riff here and there but dang... I can do a version of Little Wing and I can play most of Wait 'Till Tomorrow but Are You Experienced... hat's off to you my man! You have to be LOUD to play that one I think and Third Stone?... I don't Live Today!... that is an AWESOME album. You guys must have rocked BIG TIME!! 
Ultimate ROCK album, IMO.
 
J

Karyn
Has to be Deep Purple for me.
 
I listened to and experimented with a lot of styles in the late 70's early 80's but a compilation album I bought when I was 8 or 9 (because it had a Beatles track on it) (and I liked the picture on the sleeve) included Black Night and I've been a rock chic* ever since..
 
 
 
*ok,  maybe more of an old hen now..

I wore out The Book of Taliesyn. I loved (and still do) Shield. Then there is Machine Head. Wow.
I recently learned that Taliesin was a Welsh poet. I am a bit Welsh, a good bit. I need to get and read it.
 
J