Besides all the cool bands mentioned I need to bring the attention on Black Knight one of the most underrated metal acts of all time their only album "Master Of Disaster" (check my avatar sig) is a masterpiece of classic metal.
They had both a male and a female vocalist in their short career, but their voices were so akin that the album and the bonus tracks in it are not clashing at all. Songs like 'Master Of Disaster', 'Black Knight', 'Day Of The Wizard' and the amazing 'Battlefield'makes this album a genuine gem.
Sadly media and labels refused to recognize the metalness of a female lead singer and the band never fot their deserved break.
Their album was reissued as limited copy edition a few years ago, if you can get one do it!