Symphony X - Great Power Metal vocals by Russell Allen. Sure you've probably heard them though.
Genesis - Peter Gabriel era has ethereal vocals. Gotte respect Genesis.
Amorphis - Eledgy & onward has a lot of clean/harsh mixed vocals for good contrast, but the clean vox are great.
Devin Townsend - Great range of style & development.
Yngwie Malmsteen - Always got some of the greatest vocalists IMO. Start with his early stuff, which is mostly all good. As he progressed he got hit or miss, but mostly miss
