Wow, game OSTs.. I'd have to say my favourite right now, and FAR FAR ahead of any of the others if the soundtrack from the controversial VN "
Katawa Shoujo"
Seriously, listen to these, it's breath taking:
http://r-a-d.io/ks/bgm//Innocence.ogg
http://r-a-d.io/ks/bgm//Moment_of_Decision.ogg
And as my runner-up, c'mon, how do you beat.. Mega Man 2!?