That's a super hard question but I'd have to say that The Edge's solo on New Years Day was a huge influence on me to pick up the guitar. Yes it's simple, yes there is delay but it's right it's so, so right.
Stairway to heaven. Ok i said it. But ever since i was a little kid it made my neck hairs stand up and gave me goose bumps on my arms. The tone is incredible, the phrasing is perfect.
the sheer magnitude and bombasity of the rhythm behind it carry that solo into eternity. one for the ages.