I started with pop in the '90s, game music not really something I thought about despite playing so many titles. Then I started listening to my dad's classic rock CDs and old records but it wasn't until Guitar Hero that I went gung-ho on rock. During high school, I started to feel burnt out on rock and found techno "online". I was listening to all this cheesy arena dance stuff until one day my little bro came up to me and was really excited to share some song with me.
It was "Propane Nightmares" by Pendulum. I had never heard anything like it, so much raw power mixed in with catchy melodies and harmonies. From then on, I was into every kind of electronic music. Well then I played Skies of Arcadia and that threw me into a loop. Its music was very orchestral but also had some electronic elements to it. That game pretty much provided the final ingredient to what my ideal music was and still is: electronic that uses piano (or full orchestras, but I'm biased to piano)
A good example of that is DigiE's "Trance Turnabout". 'tis an orgasmic mix.
So yeah, just two games that really altered my musical tastes.