IM - A debut work that features a monument like Phantom Of The Opera without a single bad song "per se". And the fact that all songs are very different from one another speaks tons regarding the quality of Maiden's debut album . The title track is a bit uni-dimensional but it features that wonderful guitar and bass interlude. That being said my pick is Iron Maiden for being overplayed as hell.
Killers - Another album without fillers. Perhaps the most lose and aggressive they ever did. And by the way it was the first vinyl I ever bought. It's kind of hard to nominate a "least favorite" in such a stellar work although I think the least interesting track may be Another Life. Nevertheless it is pretty enjoyable.
TNOTB - Easy: Gangland. Why? Murky, unimaginative and straight forward poor composition that fails in its premises: delivering energy and heaviness. I agree that the lowest point of the album is Invaders chorus (what is that crap?) but the rest of the song is nothing short of amazing and it is my favorite Maiden bass line EVER (and being Harris the bass player he is, that alone speaks for itself).
POM - Another easy pick: Quest For Fire. Poor lyrics, Bruce's falsetto during the verses are horrible, uninspired mid time pace. The chorus is ok, though.
Powerslave - No fillers here and therefore a hard pick. I think it has to be Flash of The Blade. still a great song though.
SIT - Ah! My favorite Maiden record. Now we're REALLY entering the "absolute no filler" zone! And there will be people here wanting to strangle me but my pick has to be the last two songs (Deja Vu and Alexander The Great). Although being both excellent songs I think they rank down a fraction of a millimetre comparing to the perfection displayed during the first six songs. While Deja Vu is just a tiny bit too simplistic, Alexander sometimes gets a bit out of the pace of the album (uptempo with sci-fi ambiance). This was the 1st metal record I ever heard back in 1987 so it would grieve me to point it any flaw... and it really has none!
SSOASS - Picking the worst song out of arguably the most solid Maiden album (and one of my 3 favorites) is almost impossible. That being said I'll say that the song that I skip the most is The Evil That Men Do but mainly due to overplaying alone. Another Maiden record (3rd in a row) without "weak" songs.
NPFTD - Now here we have a couple of weak links . Unlike many I think NPFTD is a really nice record that only seems worst because it was released after a spree of 4 records with a single filler (!) and more than a dozen of instant classics. It features some great cuts like Tailgunner, Fates Warning, Run Silent and Bring Your Daughter (yes it is one hell of a track despite its corny lyrics). It also has cool songs like Mother Russia, Public Enema (regardless its crappy title - pun intended) or Holy Smoke (love this song... hell of a rocker but it seems completely out of place regarding the rest of the album and would give an excellent B-Side) . That being said the ugly duckling in the room is Hooks In You. It has a cool chorus but the rest of the song is a horrendous and flaccid rocker that serves as the herald of the misery that was coming.
FOTD - Maiden have records like TNOTB and POM where the weakest links are immediately detectable among so many great tunes. Then you have FOTD which is the complete opposite. Be Quick Or Be Dead is an immediate standout due to its brutal attack and breakneck speed. The eerie Afraid To Shoot Strangers with its gorgeous guitar harmonies in a crescendo of intensity and pace also grabs your attention immediately. Finally a good (although hugely overrated imo) title track with a cool intro and excellent mid section. Childhoods End and Judas Be My Guide are also enjoyable. Then it all goes south... Fugitive is ultra-uninspired Maiden 101 and Chains of Misery is pretty sloppy. Besides these tracks I can't put it any other way: FOTD as an whole is the all time low of Maiden's discography BY FAR. The vocal performance is poor and the majority of songs don't even sound like Maiden. Weekend Warrior is meh... ok I guess.. but absolutely out of place in any Maiden context (a relaxed rocker about Hooligans would be interesting as a B Side or at one of Bruce's 1st 2 records... but in this context sounds ridiculous). Worst: From Here To Eternity, Wasting Love, Apparition is Maiden playing USA inspired hard-rock-AOR-whatever crap. HORRIBLE! But I think the biggest turd among turds is Fear Is The Key... a horrendous attempt to capture a "Kashmir" ambiance that degenerates into a nauseating abomination. That is my personal pick... but the previous 3 I mentioned are also fair choices regarding how much they suck!
TXF - IMO this was the album that saved Maiden. Yes it's a pity it features a poor vocal performance by a totally out of his ambiance Blaze Bailey but that's the only letdown here. If the singing on TXF was done by Bruce or even Blaze nowadays (although still not on Dickinson's level, Bailey is singing 100 times better than back in 95) it would be a monument. And even with that drawback, as far as I'm concerned it still is. All that hard rock crappy uninspired stuff from FOTD went out the window being replaced by dark introspective epic as hell metal anthems (Sign Of The Cross, Fortunes Of War, Edge Of Darkness) or straight to the jugular heavy attacks (Man On The Edge, Lord Of The Flies). Now...besides its great leads a nice bridge and a superb chorus the only track that features a dysfunctional structure and a couple of cringe passages is The Unbeliever... so this has to be my pick. If it became a B side instead of Judgement Day TXF would be even better than the decisive album in the band's career it was.
Virtual XI - With the exceptions of Futureal, The Clansman and The Educated Fool, all we have in VXI are uninspired and boring Maiden tunes. Hey... but at least they sound like Maiden. Sure they do... with THAT ONE EXCEPTION. The single edit is bad and corny enough (oh those dreadful keyboards a la "Jump"... the horror!) but when you drag the martyrdom that is The Angel And The Gambler through 9 plus minutes (with the chorus being repeated 27 tims!!!!) it ascends to the infamous elite of the worst songs the band ever wrote. Awful!!!
BNW - I think this record was written on the run. One easily can notice songs like Blood Brothers or Wicker Man (among a couple others) were written and composed first, with time to correct imperfections (thus resulting in great tracks) while songs like Ghost Of The Navigator seem like a patchwork of great riffs that don't flow together. Dream Of Mirrors has a great chorus and passages but ends up being boring due to an awful intro and a the fact that it repeat itself way more times it should, becoming redundant. Speaking of repetition: the title track. Gorgeous intro and crescendo... it's that kind of song that reaaaaaaaaaaly builds momentum. And where does it lead us? To a Fear Of The Dark meets The Angel And The Gambler chorus, reeking of repetition that drains all the energy the 1s part gathered and the rest of the song is merely a merry go round at a faster pace, completely ruining a great opening. But the poorest composition here may be The Mercenary... as generic and flat as maiden can get.
DOD - When you have a good solid album (not one of their best but still good) it's easy to spot the weakest links. New Frontier is a bit uninteresting (sorry Nicko) but the worst song by far on this one is Age Of Innocence.
AMOLAD - As far as I'm concerned this is the band's best work since 1988 and maintains that status to this date. And hell! Not a single weak song! Different World may have one of the weakest bridges the band has ever made, but the rest of the song is catchy as hell. The longest songs are all top notch (some better than others but all have in common a high level of quality). So I'm forced to agree that the remaining two (Pilgrim , Out Of The Darkness) are the least brilliant of the pack, although being great tracks. So I'll pick The Pilgrim.
TFF - It's true that TFF is not as good as the previous 2 albums but fact is there's not a single track here I can call a stinker. I'll nominate a song that although being good tends to get a bit boring: The Man That Would Be King. Great composition though.
TBOS - A lot of great songs (the title track is out of this world!) but there's this track that sound lazy and disconnected. Shadows of The Valley starts with what seems to be a feeble self plagiarism (Wasted Years anyone?) and then goes to a completely different place breaking all the sense of coherency. Man Of Sorrows is also a bit forgettable but my pick is really Shadows Of The Valley.