Eddie Hazel. Joined Parliament/Funkadelic at 17 and was one of the key components of their sound for their first trio of records (and sporadically afterwards as well as doing some stuff with the Temptations). Not only a key player in funk he was also a blinding psych rock guitarist, as evidenced by the whole of Maggot Brain. Probably my favourite guitarist of all.
Regardless of how much I listen to him these days…Tom Morello is always the one who jumps into my head when i hear this question. Was absolutely obsessed with him when i was learning to play and still think he stands up as one of the best