wow, this topic is quite old, ehem
anyway, here are mine
Yoshiki – X Japan
hide – X Japan
Tuomas Holopainen – Nightwish
Tobias Sammet – Edguy & Avantasia
Roy Khan – Kamelot
Simone Simons – Epica
Tarja Turunen – (Ex)-Nightwish
David Garrett – David Garrett
Sharon den Adel – Within Temptation
Asis Nasseri - Haggard