[Warning: Corny Xanadu-fangirling down below. Read at your own risk.]
Red Barchetta is my #2 from this list (my real #2 is Time Stand Still). But Xanadu, and I may or may not be overrating it, is perhaps the best song I've ever heard. I think I like it more than any Maiden song, more than any GN'R song, etc. I love Rush, but I really do think this song shits on Rush's catalog and many other bands' catalogs. It's the perfect marriage of an interesting piece and a moving melody. Yes, I believe it's just as moving as Limelight and Subdivisions, maybe even more so.
There's just... something about it. It's a special song. The Holy Grail of Rush. There are no standout players in the song. Everybody has magnificent moments. You have Geddy laying down some groovy bass, atmospheric synths, and gorgeous vocals. You have Alex with his superb guitar work and that heartbreaking guitar solo. You have Neil doing fuck knows on his drumset (how many percussion instruments does he even use in this song?) and his poignant lyrics. I think the difference between this song and the ones remaining is that this one is just so much more dramatic. And every little detail enhances the song. Even as simple as adding one loud synth note, or putting some chimes in one spot. You just always find something new to love about it.
But I actually think the most moving Rush songs have already been eliminated. Red Sector A, Time Stand Still, and Mystic Rhythms. I also think Closer to the Heart is beautiful, but songs shorter than 3 minutes don't seem to last in these survivors.
Earthshine and Dreamline are pretty devastating, too.
I agree with Foro on why Red Barchetta has zero votes. It's literally just coasting by. Not that I mind, but if it outlasts Xanadu... no song deserves to outlast Xanadu.
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Now, all that said, I would like to say I'm really happy to see how long Limelight and Subdivisions have lasted. Though I think Xanadu is the more moving song, I think these are moving, too. There's such melancholy in these two particular tunes. They may not be the most technical songs, but they make you feel something, and that's more important to me at the end of the day. This is an excellent top 5.