My son Shlomik loves music. When he was less than a year old, Бременские Музиканты (Bremenskiye Muzikanti) was all he needed. He could watch over and over and really loved music and singing. A couple months ago I found the cartoon По Дороге с Облаками (Po Doroge s Oblakami) about which he's also now crazy.
Recently I introduced Shlomik to something different and the result is amazing. I often listen to Kawaii Radio on Winamp. Unlike other Japanese radio stations, they only play songs from anime. One song in particular that I decided to look up on YouTube was Ike Ike by Hinoi Team. The moment Shlomik saw the video and heard the music, he was hooked. He learned how to pronounce Ike Ike and is asking for it constantly and after he finishes watching the music video, it's around three minutes, he says "more." He loves the video so much that he even tries to mimic the moves, or at least claps. If he dares to learns more of the lyrics than I, no more Ike Ike.
Hinoi Team have another song, Night of Fire, which is fun to watch but not as good. I saw some of the other music videos, but they weren't even as good as Night of Fire. Shlomik also responded well to Shangri-la and Asu e no Brilliant Road by Angela, though nothing comes close to Ike Ike.