Anyway, tough one. Couldn't name just one. A top 5 (including my favourite songs from the soundtrack) would look something like:
Battle Arena Toshinden 3 [no, really] ( http://www.youtube.com/watch?v=mDe-KtCD10w )
Final Fantasy VIII ( http://www.youtube.com/watch?v=RVkcmx2l3WA )
Spyro: Year of the Dragon ( http://www.youtube.com/watch?v=xI2px-YGUSA )
Timesplitters 2 ( http://www.youtube.com/watch?v=3ktaQPVBsUk ) (I know it's from the first game, but it's included in the second, which overall was better)
LittleBigPlanet 2 ( http://www.youtube.com/watch?v=xRV4-IzfGY8 )