Music As far as I know, Ayaka's singing so far has only been PGSM related. Since she plays a character who is an idol, it was inevitable that she had more songs than the other characters and that those songs were played frequently throughout the show's run.
C'est la vie This is sort of a theme song for both Minako and PGSM and is played a lot of times throughout the series. It's the first single on Minako's album Venus that launched the superstar/idol status she has. It is also a clue left behind for the enemy, since Minako also acted as a diversion from the real princess. The words "C'est la vie" is sung exactly like "Sailor V" is pronounced. Usagi adores "C'est la vie" and has sung it to herself more than once. It's a very happy song with a melody that's very easy to remember.
Katagoshi ni kinsei This song was rarely played in the show. The first time it was heard was when Usagi and Minako were sitting in the ferris wheel together. Minako sung the song acapella and told Usagi that it was from her new single. Another time it was played was when Rei was sitting in the meeting room at the Crown and reflecting on Minako while listening to this song that was playing on the radio. It's a slow, mellow song and the lyrics were written by Takeuchi Naoko.
Romance A very popular Minako song (at least among other PGSM fans I've talked to). This song was first played in the background while Minako was doing a radio interview but later at a concert at Usagi's school. Minako performed with a simple dance, using hand movements mostly. She also performed "Romance" at a larger concert but due to her illness she fainted in the middle of the song and was unable to continue. "Romance" is a very happy and bouncy song. If you happen to be a fan of it, go to the fanlisting and join!
Kiss! Kiss! Bang! Bang! Minako was scheduled to record this song when she suddenly decided that she should give up singing because she had so little time left. But Rei and her manager came up with a plan that would make Minako realize that she did not really want to quit. Fortunately for them the plan worked and at the end of the episode Minako went on to record "Kiss! Kiss! Bang! Bang!". It's a very bouncy song, but with lyrics about sadness and that you don't always have to be or appear happy.
Sayonara ~ Sweet Days In my opinion, out of all the songs that Minako sung this one left most of an impact. It was played in a very powerful scene, when the girls found Minako's farewell letter at the Crown and imagined her first singing "Sayonara ~ Sweet Days" and then reading her own letter aloud and saying farewell. In the middle of the second song it suddenly cuts back to reality, where the four girls and the cats sit in silence and start to cry knowing that Minako is dead. "Sayonara ~ Sweet Days" is a mellow but also happy song, which is a great contrast to the silence and the tragedy behind it. You can download a clip of the scene here. If you like this song, please consider joining the fanlisting.
Friend This song is not sung by Minako/Ayaka on her own, but by all five girls on the show. Like the title reveals it's a song about friendship, very fitting since it was played at the end of act 49 when the girls saw Usagi again, ran towards each other and met in a big group hug. It also stayed during the credits that showed a few highlights of the show and to the end when all five girls walked away together. This song (like many others on this list) was also performed on the Kirari Super Live show.
I'm here As far as I know, this song was not played on the show. It is, however, sung by Minako/Ayaka and was released along with the first four songs mentioned above on the "I'll be here" album. It's more of the style of "Katagoshi ni kinsei" but with slightly stronger vocals and less mellowness.
This is sort of a theme song for both Minako and PGSM and is played a lot of times throughout the series. It's the first single on Minako's album Venus that launched the superstar/idol status she has. It is also a clue left behind for the enemy, since Minako also acted as a diversion from the real princess. The words "C'est la vie" is sung exactly like "Sailor V" is pronounced. Usagi adores "C'est la vie" and has sung it to herself more than once. It's a very happy song with a melody that's very easy to remember.
This song was rarely played in the show. The first time it was heard was when Usagi and Minako were sitting in the ferris wheel together. Minako sung the song acapella and told Usagi that it was from her new single. Another time it was played was when Rei was sitting in the meeting room at the Crown and reflecting on Minako while listening to this song that was playing on the radio. It's a slow, mellow song and the lyrics were written by Takeuchi Naoko.
A very popular Minako song (at least among other PGSM fans I've talked to). This song was first played in the background while Minako was doing a radio interview but later at a concert at Usagi's school. Minako performed with a simple dance, using hand movements mostly. She also performed "Romance" at a larger concert but due to her illness she fainted in the middle of the song and was unable to continue. "Romance" is a very happy and bouncy song. If you happen to be a fan of it, go to the 
Minako was scheduled to record this song when she suddenly decided that she should give up singing because she had so little time left. But Rei and her manager came up with a plan that would make Minako realize that she did not really want to quit. Fortunately for them the plan worked and at the end of the episode Minako went on to record "Kiss! Kiss! Bang! Bang!". It's a very bouncy song, but with lyrics about sadness and that you don't always have to be or appear happy.
In my opinion, out of all the songs that Minako sung this one left most of an impact. It was played in a very powerful scene, when the girls found Minako's farewell letter at the Crown and imagined her first singing "Sayonara ~ Sweet Days" and then reading her own letter aloud and saying farewell. In the middle of the second song it suddenly cuts back to reality, where the four girls and the cats sit in silence and start to cry knowing that Minako is dead. "Sayonara ~ Sweet Days" is a mellow but also happy song, which is a great contrast to the silence and the tragedy behind it. You can download a clip of the scene 
This song is not sung by Minako/Ayaka on her own, but by all five girls on the show. Like the title reveals it's a song about friendship, very fitting since it was played at the end of act 49 when the girls saw Usagi again, ran towards each other and met in a big group hug. It also stayed during the credits that showed a few highlights of the show and to the end when all five girls walked away together. This song (like many others on this list) was also performed on the Kirari Super Live show.
As far as I know, this song was not played on the show. It is, however, sung by Minako/Ayaka and was released along with the first four songs mentioned above on the "I'll be here" album. It's more of the style of "Katagoshi ni kinsei" but with slightly stronger vocals and less mellowness.