Hmm. I would say 'The Light' or 'V', whichever is easier to find. Those being the debut and their fifth album, respectively.

The Beard (in the Neal Morse led era) was a generally lighthearted, rocking take on a lot of facets of classic prog rock bands including Genesis, Gentle Giant, and Yes. If you're familiar with Neal's solo work (outside of 'Sola Scriptura' which is a bit different), you may have an idea of what to expect, though I like the Beard the best as a backing band rather than Mike Portnoy plus whomever is around at the time.

Neal has an easily identifiable style of songwriting which can turn equal parts inspired gold or boring repetition. As albums, the Morse-Beard tends to lean towards either extreme; either solid, or not. After Neal Morse left, Nick D'Virgillio (drums) took over on lead vocals and more influences and textures were added to the band's established sound, especially in the keyboard department, evoking everything from Floyd to Jon Lord. That newer era also has a lot of good material and the self-titled disc or 'Feel Euphoria' would be a good place to start there.
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Dark motions, black eyes, and mournful lust, the wings of solitude
...I'm the hateful raven
I dream in shades of you.