Not sure if I can pick just one, but here's a few off the top of my head:
Savatage: Gutter Ballet, Edge of Thorns, The Wake of Magellan
Trans-Siberian Orchestra: The Dark
Dream Theater: Voices, Scarred (Awake was a really good album for John Petrucci!)
Symphony X: Through the Looking Glass (part III)
Ozzy: No More Tears
Crimson Glory: Burning Bridges
Balance of Power: House of Cain
Blue Oyster Cult: The Siege and Investiture of Baron Von Frankenstein's Castle at Weisseria
Gamma Ray: Rebellion in Dreamland
Queensryche: Eyes of a Stranger, NM 156
Scorpions: Still Loving You
Star One: Star Child
WASP: The Headless Children
Cirith Ungol: Chaos Rising