I'm not sure I have a favorite song.. The first one I ever heard was Smily... Saw the video on youtube and just fell in love with Ai. Then I moved to many of her most popular upbeat singles.. Now I mostly listen to full albums, because all of her songs are just so good. These days my favorites are Daisuki Dayo, Kingyo Hanabi, and Yumekui. It's interesting that her fans are so diverse, and so many different songs are listed as people's favorites. Renai Shashin and Neko Ni Fuusen are two of my least favorites, but I love seeing them atop other people's favorites lists.. It's funny, my least favorite Ai songs are still better than most other artists' best songs, I think. ^_^