Super Tripe
If you take the X-Men Legends engine and wrap it around the entire Marvel universe, you end up with Marvel Ultimate Alliance. A Marvel Comics fan's dream come true. With over 140 unique characters entwined in the story, this is one of the most comprehensive comic book games every created. Over 20 of those are actually playable and the list varies depending on your system of choice.
Marvel Ultimate Alliance supports up to four players co-op, which makes for a great party game. This is amplified by the fact that the learning curve is very shallow, and the gameplay is fairly simplistic. The good news is this makes it easier to get a group of people together to play, but it's bad for someone like me that wants a deeper experience when playing solo.