X-Men First Class - or X First Class if you go by the title screen (2011)
Chosen by me as I go to the cinema a lot and like the X-Men movies (The Last Stand is awesome y'all)
Matthew Vaughn has stated he wanted to make it like a '60s Bond film but really with the split screen antics he uses at one point it's more like one of the 60's Bond film knock-offs. It's a solid and fun film for the most part, though a touch too long, especially considering it spends no time at all giving any of the students or henchmen characters - a heel turn seems especially arbitrary and a death has little to no impact at all except to note cynically that neither of these happen to the white cast (though the betrayal would make much more sense for the one who dies with the reason he gives for his pretend betrayal actually working as character development tied into his powers).
Emma Frost is the most egregious example. January Jones has little of the confidence needed to make that character work (compare the way she seems in those outfits with Diana Rigg's Emma Peel the clear inspiration for Frost) but the writing certainly doesn't help and she disappears for a huge chunk of the film.
The film really fires when it comes to the Xavier, Magneto, Mystique stuff (setting up an interesting triangle not really seen in the comics) although it has the 'going through the motions' feeling prequels can have.
McAvoy is good and Fassbender is excellent (though he gets some ungainly soap box speeches to work through).