It had been bothering me for a while...

I finally know now. I had been watching Princess Tu Tu on OnDemand, and every single time I heard the opening, I would think 'Damn! This sounds just like Furuba!' and then promptly forget to look it up when I went on the computer. But today, I rememberd! I forgot the other thing I orginally got on the computer for though... The OP to Furuba and Princess Tu Tu ARE sung by the same person, Ristuko Okasaki. ::sighs:: My ears are really good when they want to be... but never at any other time...