Devil May Cry and Marvel: Ultimate Alliance. Basically, Marvel: Ultimate Alliance with a MUCH IMPROVED fighting system. Stylish combat, intense difficulty, mission ranking system, character customization, 4-player co-op, what's not to love?
EDIT: Also, Dungeons & Dragons: Shadow Over Mystara and Exile 3: Ruined World. - Branching paths through levels, awesome beat-em-up combat, and cool secrets, combined with a huge open world, the gradual destruction of the world by rampaging monsters (to deter you from screwing around doing random side stuff for too long), character customization, and sweet magic spells? Awesome.
EDIT: Any RPG and Paper Mario. Action Commands > Random Chance. That, and I'd prefer to have more than 2 party members fighting at a time.