Steve Vai in... basically anything and everything he's done. One of my favourite bits is in Touching Tongues, and Devin Townsend is a fantastic singer. Pity he ruins himself in Strapping Young Lad and The Devin Townsend Band.
Joe Satriani, again in everything he does. Ice9 is a quirky piece that always makes me think of an old skool arcade game - unsurprising considering he writes music for them! Of course we also have the obvious: Surfing With The Alien, Satch Boogie etc etc.
And then we can go down the totally different route of metal bands - Dimebag (R.I.P) in Cemetary Gates proved that Pantera truly had use of one of the best guitarists of the genre.
Also holding on to that style we have Zakk Wylde with his numerous awards and recognition. One of my favourite pieces of his is in the middle of In This River, when he's standing in the water having just smashed the piano up (if you've seen the vid).
On a slightly different again tangent, Eddie Van Halen. Who can deny this virtuoso his title as one of the greatest? 5150, Panama, Top of the World - all fantastic in every aspect, but even better in their respective solos.