"Awkward Justice", Tales of the Abyss. Usually plays when you're fighting one or more of the God-Generals. Just so you know how good this track is, it plays multiple times as you face recurring enemies, and yet it never loses its sense of urgency.
"The Sun Rises", Okami. Plays next to one of those crowning moment of awesomeness during the last stage of the very final boss fight. The music pretty much lets you know you're going to win the fight and sets it up triumphantly.
"Counterattack", Shadow of the Colossus. Not sure on what colossi this plays, but it's usually once Wander has finallyclimbed all the way up and is going stabby. Cue aircam and flying jets of black blood.
"Red Pyramids", Silent Hill 2. Plays during the battle against the twin Pyramid Heads. The grindy saws, the ominous booming, the industrial machinery in the background... "Violent Maria" is a nice contender, for the fight that promptly follows this one. Pure despair.
"Smoking Roll", God Hand. You gotta love the Elvis Presley hum-drumming and how coolly the music plays out. To me, it defined the game then and there.