all of Savatage's albums are essential, except for maybe FFTR.
Sirens: Sirens, Holocaust, I Believe (one of the best Savatage songs EVER!)
The Dungeons Are Calling - TDAC, By the Grace of the Witch
Power of the Night (highly underrated album) - Warriors (one of the best Savatage songs EVER!), PotN, Necrophilia
Fight For the Rock - The Edge of Midnight, Hyde
Hall of the Mountain King - Beyond the Doors of the Dark (one of the best Savatage songs EVER!), Legions, HotMK, Devastation
Gutter Ballet - Of Rage and War, GB, When the Crowds Are Gone, Unholy
Streets - Tonight He Grins Again, St. Patrick's, Ghost in the Ruins, If I Go Away, Somewhere in Time/Believe
Edge of Thorns - EoT, He Carves His Stone (one of the best Savatage songs EVER!), Follow Me, Conversation Piece, Miles Away, Sleep (one of the best Savatage songs EVER!), and, if you have the Japanese import, Shotgun Innocence. Sorry I couldn't narrow it down any more than that, but it's my favorite cd.
Handful of Rain - HoR, Castles Burning, Alone You Breathe
Dead Winter Dead - This is the Time, Starlight, One Child, Not What You See
The Wake of Magellan - Turns to Me, TWoM, The Hourglass
Poets and Madmen -Stay With Me a While, Commissar, Morphine Child, Surrender