I probably won't vote her, sorry! I think Ai did really good in 2004. Ayu was alright...
edit:I voted Ai Otsuka for female, Tackey & Tsubasa for male since I liked that One Dream song (I don't listen to any male singers!).
In 2004, Ai had Love Punch, Kingyo Hanabi, Happy Days, Daisukidayo, Love Jam and possibly Amaenbo. That's her best year since she only had Momo no Hanabi and Sakuranbo in '03.