I think my favorite country for movie posters just might be Japan. I like posters that are a bit out of the ordinary and Japan can tend to get really out there with their designs. I especially like what they were doing with American horror films in the 70s and 80s. A lot of the time the posters are like very chaotic collages - movie stills, art from other posters for the film, and Japanese characters splattered seemingly randomly around. It's fascinating really, I could look at them for hours.
The Evil Dead. This poster damn near out-kitsches Army of Darkness' Japanese poster. Not nearly as cool as the one for AOD (and really, what could be?), but this thing is still absolutely bananas.
Now a hysterical poster from John Carpenter's Halloween. At first glance, this poster is fairly kick ass. It's simplistic, but very moody and sinister at the same time. But wait! Take a look a Mikey's face. Whoops! I like to imagine this guy was just really blitzed while he was painting this at the last minute, desperate to make a deadline and he just accidentally went a little too "bulgey-eyed puppet man" with his depiction of Michael Myers.
Texas Chainsaw Massacre - The collage-like design really works quite well here. Like a page from some demented scrapbook that might've been kept on the premises of the Sawyer compound. What all the Japanese stuff would be doing on there, I do not know, but you see what I'm saying.
Re-Animator - A masterful classic, brimming with severed head eroticism. Gotta love the blood splatter to hide Barbara's business. I don't know if that's supposed to be funny, but....