Actually, it was Hotel California. The first one I learned to play all parts for was More Than a Feelin'. The first album that really got me thinking about it for my own originals would have to be Iron Maiden - Piece of Mind.
The first i'd noticed it was likely Queen, but there were classical pieces written for multiple guitars! While maybe not featuring straight single note lead lines, featured plenty of harmony between both instruments!
Off the top of my head, probably Queen and Thin Lizzy. Then, Kiss “Detroit Rock City” which was basically a Thin Lizzy rip anyway. As someone mentioned earlier, the harmony on “Can’t Get Enough”. I’m sure there’s some I’m forgetting but those are a few big ones.
for me highway star by deep purple. that was the first solo me and another guitarist tried to do. later when i got into Judas Priest and Iron Maiden that was already a given. one thing that bothered me though was that live Blackmore didnt even do the same solo. and when i did it with a one guitar band, i let the keyboard player do one part. of course later since i preferred to be the only guitar player i bought a boss ps3 for the harmonies
Ramblin’ Man... it was a crossover hit on AM Country radio and that’s all my Dad listened to in the car when I was a kid. Even back then, long before I was a player, there was something about it that caught my ear.
Remember having the same impression when I first heard Detroit Rock City