For me, it's not really such a tough choice. There's a lot of great tracks in that list, but ..
The first prog epic I fell in love with was ELP's Tarkus which I think is absolutely brilliant despite their waning popularity with the prog crowd. It would probably rank as number 2 on my own personal list. However, it doesn't measure up to the brilliance of Yes' Close to the Edge.
Rock music has never since been as beautiful
