I've only heard one of their songs too! But it's the only male Japanese song I've ever liked.
Sorry to all the Ayu fans, but 2004, though it was good, was not as good as previous years. Ai Otsuka had all her music except Momo no Hanabira & Sakuranbo come out in 2004 (Though both were on the LOVE PUNCH album), which would make 2004 probably Ai's best year ever.
I don't listen to any male singers/bands so I picked Tackey & Tsubasa as they are the only male singers I can stand. That One Dream etc.. song was actually really nice!