I can't pick just one band, however, I clearly remember the first time I listened to
- Black metal as a genre
- Aphex Twin
- Aenima by Tool
- Traversee by Year of no light
- Black Sabbath
- Industrial Rock in general and Downward Spiral by Nine Inch Nails in particular
- Hyperballad by Björk
I'm sure there are more if I think for longer.
UK maybe?