hmmmmmm......
For SymX, i'd have to say, Sea of lies, especially after the legato triplets part. Not -that- technical but it sounds damn good with the song.
Others, in random order i can think of include:
Rusty Cooley - The Butcher, Under the influence, Jasmine's song, Dominion
Megadeth - Ashes in your mouth, Hangar 18, Set the world afire
Sonata Arctica - Black sheep live version, Last drop falls, Wolf and raven
Sinergy - Midnight madness, Razorblade salvation
Children of Bodom - Bodom after midnight, Downfall
Ayreon - Chaos, Dawn of a million souls (with our very own Russ at the mike!!)
Judas Priest - Painkiller
Helloween - Eagle fly free, Wake up the mountain, Before the war, March of time intro
Testament - Confusion fusion, The legacy