If you want to list your favorite Vocaloid Songs, go here.
Supercell member ryo's version of Melt has a crowning moment at 3:30 when Miku becomes fully animated.
Sekiranun Graffti, also by supercell, has a beautiful, and fantastically animated PV that just makes you happy to be alive.
Lience may not be a word, but the song itself has the potential to blow your mind. A slow, moderately-paced build up to running for your life from a crazed yandere miki was enough to give This Troper goosebumps!
The incredibly realistic scream from Kiyoteru at the end of Guilty Verse
Miku Hatsune live in concert.. Apparently there are plans to bring in the other Vocaloids at the next Mikufes.
And then they went and topped themselves with the 39's Giving Day show, a full two-hour concert with more advanced projection technology, full-motion capture, and appearances by three other Vocaloids to sing their own hit songs. And it was AWESOME!
And now they've come to America. The concert actually sold out two weeks before the day itself (the organizers were in fact expecting a few vacant seats so they would sell a few more tickets to early birds on the day of the concert), and they even madeheadlines.
Although the PV for Reboot is a major tearjerker, it's hard not to marvel at how wonderful the animation is. It looks like it comes straight out of Studio Bones.
Seiko-P's version of Funiculý, funiculÓ may not seem very impressive at first, especially when you consider Luka's multilingualism, until you realize that Luka's doing vibrato. This is a Crowning Moment of Awesome for the producer, because getting a Vocaloid to pull off vibrato like that is extremely difficult due to programming limitations and how the voice files work.
Not only that, but the entire song - with the takoluka serving as a chorus and conductor - is just downright adorable.
There's also the Kaito version. There are two distinct versions, by the same producer - The normal version and another version, a rap version. Now, the rap version on it's own is a CMoA, as the Vocaloid software is designed for singing, not talking, and yet the rap version sounds wonderful. But, when you combine them... You get this.
In addition, Miku's English voicebank was finally released, and available worldwide, on her sixth birthday (August 31, 2013).
Synchronicity. That is all.
This piano cover of "The Dragonborn Comes" from The Elder Scrolls V: Skyrim, featuring an awesome PV with Miku seemingly singing live next to the PV's producer himself on piano. And that's not yet taking into consideration Miku's already awesome singing (including singing in Dragon Language at the end).
This video featuring Luka Megurine lipsyncing to ABBA's "The Winner Takes It All" using Hatsune Miku Project Diva's Edit Play feature. The producer was very meticulous with the video down to Luka's lips trembling during the singer's vibrato parts.