The awe and wonder of Mass Effect was simply stunning, from the views of Space and the Citadel, to the various alien races, to the giant scale epic wars, some of the best characters in games and of course the Ashley/Shepard romance ending and subsequent final mission just left me with this feeling at the end of pure awesomeness... like I had seen one HELL of an awesome movie.
Also got to give mention to the Halo trilogy for each time giving me something to go 'woah' at, however I won't dwell on that because pretty much everyone's aware of it by this point.