All of the Epic Classics, ala Buquebus, Rufus, Phaddy, Escher\'s, Tribal, etc, are all obviously some of their best material... but for a new listener, it might be better to stick with only one or two of those on a sample disc & stick with more short to mid-length songs....
I would suggest:
LDZ
The Chase
Buqubus
Inner Glimpse
Doughboy
Gravity / Rufus (choose one)
Earache My Eye
Attraction
Superfly / Wild Pack (choose one)
Funky Bill\'s