I would like this to be true but I seriously reckon Dr. Ray is exaggerating here. The developers who work on the game have continuously said its shorter than Baldur's Gate 2. BG 2 was about 100 + depending on how you played and if you completed all side quests.
Dragon Age Origins will be very long and offer lots of replayability but I doubt its 120 hours. From what I know I think more in the 80 hours + range.
These hours estimates are always subjectivity thought. Since its going to go quicker if you play on an easier setting since the combat will be easier and it will take longer if you explore everywhere and use every possible dialogue option available to you and read all text and listen to all dialogue without skipping.
