X-Men 2: X-Men United

The first Singer film in the series felt hampered by a studio that was nervous and a budget that couldn't really bring a full cast of powerful mutants to life. The second time out, a great strong script and a greatly increased budget gave Singer room to really rip, and the result suggested just how big and bold superhero films could be. It also finally seemed like a major studio was going to build to one of the great classic comic book stories, the Dark Phoenix Saga, instead of just reinventing something wholesale. Hugh Jackman's best work as Wolverine? Here. McKellen's best Magneto? Here. Patrick Stewart's best work? Rebbeca Romijn's best, for god's sake? Here. It just feels right, start to finish, and it's a shame we never really saw the sequel to it.