There’s only one contender…Frank Zappa. Seriously, go listen with an unprejudiced ear to some of the solos on any of his LP’s (Hot Rats is definitely a recommendation or, if you can, get your hands on a copy of Lather) and consider the range - from jazz, through funk, pop, and on to metal. Or just buy any of his instrumental releases, such as Shut Up N Play Yer Guitar or the sublime Transfusion.
