The year end podcast for 2010 featured a category for worst trend, and I got to thinking what are my favorite trends. And possibly number one for me would be controlling a peripheral character for a brief amount of time. I don't know what it is about this but several games recently have done it, and for some reason it always is one of those f-yeah moments for me.
Mass Effect 2 did it
What are your favorite trends, another honorable mention for me would be the cinematic implementation of music in a game.