Update 12/01/2009: Thank You for correcting me Mark!, it was "Mari" Iijima... one must never write posts when one is sleepy... :D
I was never a huge fan of Mari Iijima's singing of Watashi No Kare Wa Pairroto (My Boyfriend is a Pilot) in the original Macross Series. It was only when I heard Megumi Nakajima's modern rendition of the song in the Macross Frontier series was I truly impressed with it. Plus of course the animation of the singing during the Miss Macross contest was quite cute. It was great that the creators decided to pay homage to this iconic song.
This song was the anthem of the Earth forces in its fight against the Zentradis. The uncultured Zentradi forces were raised without any culture by their Protoculture creators so that they could be focused on warfare. Exposure to any form of culture (like songs, kissing, etc) came as a shock to them and could therefore be used as a tactical advantage.
Personally however, what I felt that really elevated the Macross Franchise to the beginnings of greatness and eventually the path to epicness was the song "Ai Oboete Imasu ka?" (Do You Remember Love) that was sung by Mari Iijima in the Macross - Do You Remember Love? Movie.
