Well, I haven't actually gone to see many films this year. But I'd say it's a tie between X-Men First Class, and Attack the Block.
X-Men, simply because it succeeded where Origins failed, tying itself well into the storyline and the canon. The characters were cool, the story was good, and the new mutants were pretty fun.
Attack the Block, because of its low budget feel and clever plotline. For those who don't know about it, it's about when an alien lands in a shady London estate, and is followed by dozens more highly aggressive aliens, leaving the defense of the estate up to the local street gang and drug dealer. The design of the aliens was very original (Like a gorilla/xenomorph hybrid with glowing teeth, and that's the nice version!), the kids were very convincing as chavvy thugs, and there were some genuinely funny moments. At last, a sci-fi comedy that's actually funny that isn't Spaceballs!
