He's one of the first to come to my mind in a thread like this... the greatest instrumentalists are those who can make their instruments emote like no other. I love the solo on this cover song from the Alex Skolnick Trio.

This live version is a bit lacking in video and sound quality (solo starts at 4:40)

But the studio version has proper instrument balance and the guitar overlays make a bigger sound space (solo starts at 5:15)

Another underrated guitarist, Greg Burgess (from Allegaeon) is another metal guitarist with classical guitar roots... both styles showcased in the same song.

And the full-length classical guitar outtake...