Both Aramis and Kensee are correct. Terra misses the boat for a change. "Number One" is a great song that is overplayed in the anime. Wish there was another "optimistic battle music" theme once and awhile... You know, something that could fit the mood for more serious battles where Ichigo is not quite so confident as desperate and grittily determined to win or die trying. Number One works best when he's acting all cocky and surprising his opponent with his resilence and natural skills.