A good video game soundtrack that promotes a good feel related to whats happening during the game will easily make me like the game much more than a game that doesn't do this.
I mean, look at RPGs for example (like Gare said)
but even better, look at shumups. Theres like, no emotion to what the shit is going on but yet theres still this epic badass music to tell you that you are going to bust some ass today:
the music also has to be in some way unique and actually musical. This *I think* is pretty musical and unique.
