I'm sort of throwing this out here as I actually have never ranked all the studio albums from Marillion, my favorite band. And not even a top 5. Although I have written some extensive things about many of their albums, including some on this list.
I guess if I am a savant about any 1 band with an extensive catalog, that I don't find too many others champion their knowledge about, it is Marillion.
Granted I hardly consider myself their biggest fan in the world nor try and compete (even as silly as it seems to those who do). I approach artists and music like a music-listening buffet, rather than obsess over having, knowing the most about 1 artist. I am more into enjoying a boatload of artists, but not being their biggest fan, but just being a fan/somewhat big-fan.
But the 1 or 2 exceptions is Marillion (and Kevin Gilbert) I like think of myself. Mind you, I still have no interest to know the most, own the most, or win at being the most dedicated/obsessed fan of.
So that being said, I'm posting this initial list for now of a Top 5 (and all of their albums I rate at 5-stars), with the intention of making a podcast and/or videos about either all of their albums individually or maybe 1 long podcast, including every single proper studio album (and maybe an EP or 2).
1. Brave (1994)
2. Clutching at Straws (1987)
3. Misplaced Childhood (1985)
4. Marbles (2004)
5. Afraid of Sunlight (1995)
Related: Top 10+ Marillion Songs List