I personnaly love ballads with strong and dark feelings, with very emotionnal content.
I'm not into Stryper or Edguy ballads for example
Last year I made 3 tapes compilations of my fave ones for my former girlfriend, I still have the track list
so here's a copy past below and some notes lol
K7 #1
Side A :
Judas Priest : Beyond the Realms of Death (ultimate one!!!)
Sortilège : Quand un Aveugle Rêve (amazing singing...)
Udo : In the Darkness (Udo CAN sing

Grave Digger : Ballad of Mary (Chris CAN sing too ahah, beautiful emotions in there)
Rainbow : Cath the Rainbow (Dio is God)
Pretty Maids : Savage Heart (sad...)
Manowar : Courage (live)
Dio : Egypt (unbelievable feeling in it!)
Blind Guardian : Bard Song (great live song

)
Side B :
Deep Purple : Child in Time (a classic

Gamma Ray : Silence (Queen-like, don't you think?

Virgin Steele : Child of Desolation (deeper than anything...)
Stratovarius : Forever (live)
Primal fear : Tears of Rage (most original PF song)
Helloween : Tale that Wasn't Right (another classic)
Therion : Seawinds (Accept cover)
Savatage : Believe (have you never cried listening to this one?)
K7 #2 :
Side A
Halford : Silent Scream (yeah Rob again

)
Accept : Winter Dreams
Rainbow : Temple of the King (and Dio again eheh)
Savatage : Back to Reason (Savatage is maybe the best band for that kind of song...)
Skid row : 18 & Life (remember the video!)
Gamma Ray : Pray
Dio-Malmsteen : Dream On (Aerosmith cover, unfortunately Yngwie plays too much...but Dio rules!)
Led Zeppelin : Stairway to Heaven...
Judas Priest : Diamonds and Rust (live 98, my favorite version)
Side B
Halford : Beyond the Realms of Death (live version yeah once more

Fates Warning : Pleasant Shade of Gray Part 6 (nice nostalgic feeling)
Ayeron : Tunnel of Light (Fish sounds great)
Manowar : Master of the Wind
Crimson Glory : Painted Skies
Anathema : One Last Goodbye (very depressive...)
Thin lizzy : Still in Love with You (cool blues)
Nevermore : Insignificant (I do love Warrel Dane's voice!)
K7 #3 :
Side A :
Savatage : All that I Bleed (RIP Criss Oliva, we miss you

)
Annihilator : Phoenix Rising
Hammerfall : Glory to the Brave
Iced Earth : Watching Over Me (I agree with you Final_vision

Demons & Wizards : The Fiddler
King Crimson : Epitath (not really a ballad yeah...)
Whitesnake : In the Heart of the City (oldie but goodie)
Conception : Nature Crying
Side B :
Vicious Rumors : The Voice (RIP Carl Albert)
Twisted Sisters : The Price
Warlord : Winter Tears (not really a ballad again, but very close)
Dio : As Long As It's Not About Love
Angel Dust : Still I'm Bleeding (right 13th Angel

Fates Warning : We Only Say Goodbye (great melodies)
Doro : The Storyteller
Jag Panzer : All Things Renewed
ok, that was my favorites!
