My favourites (favourite 6 in bold, sorry can't bring it down to 5 now):
"Burning Ambition"
"Sanctuary"
"Twilight Zone"
"Total Eclipse"
"I've Got The Fire" (live, 1980)
"I've Got the Fire" (studio, 1983)
"Mission from 'Arry"
"That Girl"
"Massacre"
"Kill Me Ce Soir"
"Justice of the Peace"
"Virus"
Purely focusing on material written by the band:
Burning Ambition
Sanctuary
Twilight Zone
Total Eclipse
Justice of the Piece
Virus (the last good non-album song)