I'm a huge Moody Blues fan (they're my favorite band) and this album isn't even their best. Their best album would have to be Children's Children or Threshold of a Dream. 'Days of Future Passed' can't even begin to compare, but for some reason it's the one that always gets referenced. It's overhyped, over-referenced, and overshadows the others (unfairly). I think it's the casual fans that always reference it for some reason, because that's the one that got the band started and is perhaps the most "well known" of any of their material. Personally, I never listen to it because they simply have much better material on the albums that came afterwards.
Don't get me wrong, it's an excellent album, but if you want to truly get blown away, listen to those two albums I mentioned. They will change your life.