The OST is indeed beautiful, but I haven't listened to those of every game this past year and cannot make a best OST of the year judgement (neither can any of us, really, I'd wager). In addition, there were also a few other really good soundtracks this year. Say what you want about the game, but Two Worlds II surprised me with the quality of its soundtrack and I really like Uncharted 3's. Although I'm not much of a techno music guy, Deus Ex: Human Revolution's was also pretty well-done. There are a few more I'm probably not thinking of right now and unless we're sticking to just western releases, Ni No Kuni over in Japan has an absolutely heart-melting soundtrack (can't wait for localization and release over here in the west - should be this year).
On the topic of examples:
Deus Ex: Human Revolution - http://www.youtube.com/watch?v=ym-mQlanzHE&feature=related
Uncharted 3 - http://www.youtube.com/watch?v=ZDRxuIsGUzs
Ni No Kuni - http://www.youtube.com/watch?v=ISbVq8Z9dQM
Two Worlds II - http://www.youtube.com/watch?v=WLRBHm6L_q4