There are quite a few others I'd add to the list (although I don't realy know what they'd consider a "power ballad"--does it have to do with the band having to normally be a hard-rockin' one?) How about "Feel Like Makin' Love" by Bad Company or "When the Children Cry" by White Lion or "Bringin' on the Heartbreak" by Def Leppard or "Silent Lucidity" by Queensryche?
"Silent Lucidity" is on the list!
"Bringin on the Heartbreak"...forgot about that one.