Phantom, Hallowed, Rime and Sign of the Cross are certainties. For the fifth take a pick from Murders In The Rue Morgue, Children Of The Damned, Caught Somewhere In Time, To Tame A Land, These Colours Don't Run, Stranger In A Strange Land and Lord of the Flies.
I chose These Colours Don't Run because it exited too early in the survivor series and it has the best bridge and chorus combo around.
As for the rest of the choices Hallowed be thy Name is an all time favorite. Phantom has the genius solos, the middle section is just awesome. I love Rime's first 6 to 7 minutes and the solos again are brilliant. Sign of the Cross for it's atmosphere, lyrics, chorus and killer instrumental section after the solos.