Talk Talk made their name in the 80's and achieved decent popularity by creating a bunch of new wave/synth pop tunes. Spirit of Eden, however, saw a large departure of this, instead containing a mix of rock, jazz, classical and ambient. While not as successful commercially, Spirit of Eden and its follow-up, Laughing Stock, set the scene perfectly for 90's bands like Radiohead, The Verve and helped pave the early post rock movement. But enough background/significance, it wouldn't mean anything if the album wasn't good to listen to; thankfully, it is. To be honest, I've never been able to completely 'grasp' Talk Talk's music as much as many others, but slowly I'm starting to break through this and see their amazing talent. Spirit of Eden has helped with this and I only expect it to continue as time progresses.
Runner-up AotW: Sonic Youth - Sister