Yeah, I can't really think of what my fav songs are, I'd have to say that there are so many songs that I like. Such as Rakuen by Do As Infinity (4th Inu movie), but also all the other anime, like Full Metal Panic (any of 'em), and Chrno Crusade songs (the opening especially). Musn't forget Rurouni Kenshin songs either!
Yup, there's waaaay to many for me to decide from! ^_^