The Prophecy is a gem. It was Maiden stepping out and doing something a little different. The ending is amazing and the middle instrumental section is awesome aswell.
I always loved Davey's songwriting; Prophecy, Total Eclipse, Judas Be My Guide, Brave New World, Still Life, Justice of the Peace, Twilight Zone, Deja Vu, Thin Line Between Love and Hate, Rainmaker, Fates Warning etc. all great stuff.