The whole album is great to listen to, but I picked this one because it's got a nice mix of the comedy, schizotypy, and grandiosity that I like about the album. I also rather enjoyed the fan-made video, especially with Eris and Dysnomia at the end.
Next we've got a great song from the second Liquid Tension Experiment album. This is the group that guitar virtuoso John Petrucci and Mike Portnoy of Dream Theater made along with Tony Levin and Jordan Rudess when they were trying to persuade the latter to join their band. Listening the keyboards, you can see why they wanted him. His keyboard solos are certainly the best parts for me of the live albums Dream Theater has made since then.
Say what you will about darker progressive metal bands like Symphony X, but this is joyous music. I like how the uploader put a slideshow of smiling people for the visual component, but even without them I can't help but feel bliss when I hear this song. The rest of their work (two albums) is also worth checking out, but this is definitely the capstone for me.
Third, we've got a song from Ayreon's most recent double album, 01011001, whose story inspired a previous post of mine. The song does a good job of showcasing Arjen Lucassen's interesting tastes in instrumentation, though it doesn't have one of his mind-bending keyboard or guitar solos.
My favorite part of this song is definitely the interplay between Arjen himself and Lisolette Hegt (from Dial, another band worth checking out) that starts a bit after 3 minutes in.
Finally, let's hear a song from Porcupine Tree's Deadwing album that most closely fits the progressive metal theme. This was my favorite album when I first started listening to the band, but nowadays Lightbulb Sun probably is. I haven't listened to Porcupine Tree that much lately - some of the lyrics affect me in ways I don't always appreciate - but they've certainly got some good music if you're into prog metal or psychedelic rock.
The instrumentals in this song flood my synapses with serotonin and a nice sprinkling of dopamine. I'd have embedded my favorite song on the album, but I didn't want to ask you guys to sit through a 12 minute song.
Incidentally, all of these musicians can have lines drawn between them shorter than Kevin Bacon's armpit hair. Hope you enjoyed the tunes. Now I have to sit down for another 10 minutes and listen to the rest of "Arriving Somewhere But Not Here."