X-Men: First Class
One thing I've learned from reading a lot of X-Men comics is that evil doesn't just spring up out of nowhere. More often than not it's born of carelessness: someone "good" says something thoughtless to a fragile soul on the threshold of darkness, and blammo, new supervillain. This happens twice in X-Men: First Class, which makes sense, considering how much of the movie is spent on establishing character -- or at least introducing characters.
A prequel to the four preceding X-Men movies (from the pretty good Bryan Singer-directed X-Men in 2000 to the universally lambasted X-Men Origins: Wolverine in 2009), First Class has so much fun with its setup that you almost wish it never got around to the saving-the-world-from-nuclear-annihilation plot. (Mutants solve the Cuban Missile Crisis; JFK gets credit.) It's a blast watching the young Charles Xavier (James McAvoy) and the future Magneto, aka Erik Lehnsherr (Michael Fassbender), sashay around the planet collecting stray mutants to protect and school. Even more fun is watching Lehnsherr track and punish his Nazi tormenters -- this could easily be its own whole movie. The man has flair. (And teeth! My god.)
It's also cool to see how far the characters have come. Pre-wheelchair Xavier is a little smarmy (he tries the line "that's a very groovy mutation" twice). He's idealistic and brilliant but not yet wise. He lacks the weighty dignity of the Patrick Stewart years, and we get to see him make mistakes. (See above re thoughtlessness.) Other characters arrive fully formed; there's a great cameo that damn near steals the show. Jennifer Lawrence (Winter's Bone) does a good job at toughing it out as Mystique, who must console herself with Fassbender after getting the brushoff from wimpy Xavier and nerdy Hank McCoy (Nicholas Hoult). The other young recruits are mostly props for training montages -- and the nerd in me insists I mention that Banshee (Caleb Landry Jones), although adorable, is really supposed to be Irish, and old enough to get with Moira MacTaggert (Rose Byrne).
As villains go, well, for starters you have the Nazis. Kevin Bacon makes a decent Sebastian Shaw, and the special effects around him are weird and impressive. But January Jones doesn't radiate enough intelligence for Emma Frost; the movie turns her into Shaw's penthouse playmate. She looks fabulous, though, as does the whole enterprise, particularly the bad guys' Austin Powers-y egg-shaped sub-submarine hangout.
Both silliness and sap increase as the film rolls along, but the big action scenes are handled well, and it never becomes ridiculous enough to undercut the cool, shaken-not-stirred vibe of its first half.