This one is tough.
Iron Maiden -- pass! I mentioned elsewhere why I think this song is overrated and it certainly does not compete with the talent here.
Killers -- I know this one is one of fan favourites, but I currently do not rank it as high.
The Number Of The Beast -- a great song with a memorable solo, but it does not have that magic stuff like others on this list.
Seventh Son Of A Seventh Son -- a good song, but not that good.
No Prayer For The Dying -- a song I'm liking more and more.
Fear Of The Dark -- this used to be one of my favourites, but it dropped down in ranking. I'm not sure why; maybe because I'm over-hearing it to death.
Dance Of Death -- it is the "... and I pranced" that makes this song less than appealing as the next two.
Brave New World -- this could have been my favourite, but I opted to go for the next one which is growing on me more and more...
Powerslave -- a song that gets better every time I hear it. Moody, powerful, mysterious. I vote for this one like most it seems.
EDIT: I can't believe SSOASS received so many votes and the two newest songs so few.