John Petrucci's awful vocal demo of The Spirit Carries on always makes me laugh... it's hardly a masterclass in performance but sometimes it's more joyful to just listen to musicians having fun, y'know? Having a laugh. And that one fits the bill.
I'm also a huge fan for Another World, everything from the way it just explodes into the opening from the previous section, to the impassioned vocals, to THAT Petrucci solo... fantastic.
I'm sure I could go on, but that'll do.