All great selections so far!
Mitsuda and Iwadare are probably two of my favorite composers as well, but there are some other amazing ones as well. The Nier soundtrack never ceases to evoke emotions for me.
Other favs:
Motoi Sakuraba (Tales, Eternal Sonata/Trusty Bell)
Koji Kondo (Wind Waker)
Kow Otani (Shadow of the Colossus)
Michiko Naruke (Several Wild ARMS games)
Yukihiro Jindo (Lots of recent Falcom stuff)
and most importantly Ken Nakagawa of GUST fame (Atelier, Ar Tonelico)