Here's my top 10:
10.
AAA - 恋音と雨空
I like everything they release.
09.
Katy Perry - Roar
Not really a Katy fan, but I've heard this song so often I started to like it eventually.
08.
Miracles of Modern Science - Singularity
Catchy tune, love all their stuff.
07.
Thomas Azier - Ghost City
80's beats always do the trick.
06.
Ayumi Hamasaki - Feel The Love
Loved it from day one.
05.
Miley Cyrus - Wrecking Ball
Same reason as Roar, not a fan of Miley, but after hearing it being played on repeat I started to like it a lot.
04.
Namie Amuro - Hands On Me
When I first heard the song I thought: this song could be a hit if only she sang it in English. But then I found out the song was sung in English already. Awesome song.
03.
SKY-HI - 愛ブルーム
Horrible vocals during the chorus (more specifically: the Nanananana part), but the intro and arrangement are awesome.
02.
AAA - Love Is In The Air
They can release awful songs and they will still all end up in my top 10. Love their vocals and everything else.
01.
Ayumi Hamasaki - Merry-go-round
Flawless song/music video and everything. I even like the rap part.