Cave In.
They followed a similar progression to Anathema, just in a different field. They started out as a very extreme noisecore band, mixing chaotic noisy metalcore with experimental noise sections. They subtly changed their sound for an album, then suddenly switched to a much more palatable space rock sound. Now, after 4 or so years, they have changed to a very poppy space rock sound, dropping most of their prog tendencies.
Get these songs:
Juggernaut
Requiem
Big Riff
Tides of Tomorrow
Lost in the Air
Anchor