Whatever Nobuo Uematsu touches. Michiru Oshima (Ico) and Kow Otani (SoTC) were great as well. Harry Gregson-Williams was great on MGS2 and 3 soundtracks. More recently Deux Ex HR and Xenoblade were good soundtracks within the past ~year.
I Diablo'd myself out, good thing Dragon's Dogma releases tomorrow.
Get the other two and then you might see why. Alternatively wear green, blue or red tinted glasses and just watch the one you already have.