Part 3. Gameplay is the best. Different styles makes for very fun gameplay, as well as sliding on your knees with a demon guitar. The game was actually difficult. I remember when that was a good thing. Now its frowned upon. Unless your Demon Souls. Plus you got to play a new storyline of Vergil afterward, And he was equally as cool.
Cutscenes are the best asside from "I wanted to fill your darkside with liiiiiiiiiight!"
Dante was the best. What could possibly be cooler than a half human half demon who eats pizza, and drinks strawberry milkshakes? He talks the best, kills the best, and didnt change his hair to be edgy and cool.