The highest user rated album of each genre listed on Sputnikmusic
Given how weird the listings can be with these, I had to set a few ground rules first for my picks:
For some of the genres here there are a few ratings, so while these aren't necessarily the most popular, they are the highest rated, ones with a degree of uncertainty, or that were just selected as being the best pick but don't really have too much information are labelled with an *. For this list, albums with below 50 ratings are generally not considered unless there are no viable alternatives on Sputnikmusic's charts. Repeat entries are also substituted for the next highest when the genre better suits the next highest rated.
I included repeat artists, especially because for some charts like Drone and Post Rock GYBE was like 4/5 of the top albums, but I may update to change this in the future.
Ambient*
(The charts for this genre are kind of a clusterfuck of classical, soundtracks, and other albums that only really vaguely fit the ambient description, this album is really like #7, but when you consider those things and how many have less than 50, this one was really the most fair choice in my opinion. If you're curious, though, the #1 spot was the Silent Hill soundtrack, which I included in the Soundtrack part)
Bluegrass*
(A similarly clusterfucky genre where most of the top ones are classical albums. None of the non-classical albums on this genre's charts had over 50 ratings, so I had to go with the one with the highest in general)
Britpop
(This is technically an EP but it is the highest rated Britpop release; the highest rated Britpop album is Different Class by Pulp, which is a great album if you're interested)
Folk Punk
(Another case where the highest rated is an EP, but this also has almost 400 votes so I can't really dismiss it, the highest rated album is Burn the Earth, Leave it Behind by Wingnut DishwashersUnion)
Hard Rock
(Above this album were listed Led Zeppelin IV, which would've been a repeat and Are You Experienced? by the Jimi Hendrix Experience, but I felt like this album is a better representation of hard rock being an album that actually is hard rock)
Indie Folk
(Either/Or was #1 here too, but it was a repeat)
Indie Pop
(Steve McQueen by Prefab Sprout was next up, and it's an amazing album that I would recommend too)
Indie Rock
(The first 2 entries were repeats, Either/Or and The Devil and God... respectively)
Jazz Fusion
(2nd to Kind of Blue by Miles Davis)
Melodic Death Metal
(2nd to Storm of the Light's Bane by Dissection)
Pop Punk
(Another EP, the top album was Keasby Nights by Catch 22)
Post Hardcore
(Third to The Shape of Punk to Come and Spiderland respectively)
Post Rock
(2nd to Lift Your Skinny Fists...)