I don't know! There are so many good ones and I think it is constantly changing for me. The following are some of my Kegemaran in lyrics, sound, and visual.
"Key" sejak Daisuke Ono (Psychic Detective Yakumo) "Nirvana" sejak Mucc (Inu X Boku SS) "World's End" sejak Flow (Code Geass) "Spell" sejak LAMA (NO.6) "Closer" sejak Inoue Joe (Naruto Shippuden) "Things I can do" sejak HOW MERRY MERRY (Natusme Yuujinchou) "Stray" sejak Steve Conte (Wolf's Rain) "Zero!!" sejak Minami Kuribayashi (The Devil is a Part-timer!)
But I'll go with "Izayoi Namida [Hesitating Moon]" sejak Yoshioka Aika (Hakuouki) because I could just listen to it over and over again. And I Cinta the lyrics! It basically means time is fleeting and Bunga don't last forever. But spring always comes and the cycle of life will continue again.