Devil - I cannot say enough about this movie. The story, while not all sunshine and lollipops, is as well told and sequenced as you will get. Everyone delivers a solid acting job. The twist is extremely well done even after multiple viewing. The ending is completely organic the way the movie plays out. Sucks that the movie was completely dismissed because of the big name attached to the project. Watch it, watch it twice, and then watch it again.
Chronicle - Another really dark movie that completely caught me off guard for how good it is. This is the best superhero movie of the past decade after The Dark Knight, Iron Man, and Spider Man 2.
Rum Diaries - I heard "boring" tagged to it. I thought it's only problem is that people are used to the Hunter S. Thompson of Fear and Loathing in Las Vegas and other lore, and not the quasi-romantic he was. Plus, there's plenty of drinking in this one, and Amber Heard is legitimately one of those Hollywood girls that holds up to being called beautiful.
The Innkeepers - Ti West is a really good young director, and the Innkeepers is another strong outing. Great buildup and the ending is really creepy.
The Other Guys - I love this movie. It's hilarious.
Casa De mi Padre - I love this movie. It's hilarious.
Drag Me to Hell - Old school Sam Raimi movie made in 2009. Better than the more hyped Insidious.
The Woman in Black - Radcliffe is another great young actor, and this is another remake that tops the original.
Not in the past 3 years but I want to put out there anyway:
Zodiac - A masterpiece. Probably the best movie Fincher has ever made. Probably not underrated - the movie seems to be adored online - but no one calls it one of their favorites. I haven't even seen it since it came out and I still remember how creeped out I was when Gylenhaal's character had to go down into that one guy's basement.
Charlie Barlett - Yelchin might be my favorite up and coming actor out there. Really charming movie with a STAR STUDDED cast including Big **** McGee and Downey Jr. Fright Night is another one of those remakes that does it right that the Yelchin guy is in.
Pineapple Express - The. Best. Stoner. Movie. Ever. No contest.
Now that I have written all this I regret it, but perhapssome good new movies are mentioned. I watched a shitload of movies in 2012.