To be honest, I really don't know what so good about steve vai (no offence)..
Joe satriani (Technique)
Slash (Tone)
Paul Glibert (Major Solo)
Guai Shou and Shi Tou (Again, I am a mayday fan)
Jimmy Page - the way he rocked the stage
Matt Heafy - the way he write solos (like light to the flies and in the fire)
Neil Zaza - melodious songs
John Petrucci - his sweeps
and some japanese guitarists (guys from X Japan and L`Arc En Ciel) who have their own jrock kinda tone.