Depends if I'm in the mood for
cute maki (Yaruki! It's Easy, Genshoku Gal),
sexy maki (Uwasa no Sexy Guy, Glass no Pumps),
kick ass Maki (Daiteyo! Please Go On, Yokohama Shinkiro), or
elegant/beautiful Maki (Ai no Bakayaro, Scramble, Sayonara Tomodachi..., Suppin to Namida).
If I was forced to choose it would be between Scramble and Sayonara 'Tomodachi ni wa Naritakunai no'. Those two always make me melt inside because of slo-mo Maki in Sayonara and towards the middle of Scramble when the CG hearts fly arround her

Plus it's two of her best songs.