I didn't notice before there was a Aya kamiki thread. Good idea, Yoake!
If I'm not wrong, the first song I heard from Aya was "Mou kimi dake wo hanashitari wa shinai", and after that I downloaded her "Are you happy now?" album, which is very good.
By the way, I've always thought she is the "Japanese version" for Avril Lavigne.
And about the Aya at avex thing... wow, I'm very surprised O_o