These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Sigur Rós
Best Known for the Fanservice: This seems to be happening in regards to one of the videos for Fjögur píanó (Warning: NSFW) that came out of the Valtari film experiment. It was featured on many blogs that had never before heard of the band simply because Shia LaBeouf was completely naked in the video.
Don't forget "Hoppipolla", "Sæglópur", "Untitled 1", "Untitled 2"... really, the band seems fond of this trope.
True Art Is Angsty: Their angsty songs (to be precise angsty melody since nobody understands the lyrics) from the earlier albums like Viðrar vel til loftárása, Untitled #1, and Sæglópur were received better by fans and critics alike compared to their Lighter and Softer approach for their album Með suð í eyrum við spilum endalaust.
On the other hand, by far their most popular song is Hoppipolla, which is definitely Lighter and Softer.
Also, ( ), being the moodiest of their albums is often considered one of their weaker works.