There are too many to name! But there's one that's so simple it really blew my mind when I suddenly noticed it after years of listening to The Divine Wings of Tragedy. In The Accolade, 2 minutes in, the riff is exactly like the main riff from Of Sins and Shadows, but only for about 12 seconds before changing into the new main riff for the song. I love how it's so subtle but ties the songs together musically.
To name another, at about 6:45 in the title track on The Odyssey, it sounds like a reference to Cygnus X-1 by Rush.
I'm a little overwhelmed by having found this thread. I have to stop before I stay up all night listening to every SX song and finding something to comment about!
/n00b
//only to the forum, not the band!