How about a little from each album (except the debut):
Of sins and Shadows
Sea of Lies
Smoke & Mirrors
Church of the Machine
The Damnation Game
A Winter's Dream I & II
Communion & The Oracle
Rediscovery I & II
Accolade II
King of Terrors
And close with the classics:
The Divine Wings of Tragedy
The Odyssey
That's as complete a compilation as you could make. That's a lot of material though, probably more than 1 CD (88 minutes at least), so cut out The Odyssey and 1 song from each album.