Recently I enjoyed "The Sparrow" by Mary Doria Russell. Well, maybe "enjoyed" is the wrong word... It's a first contact story with a lot of interesting and quirky characters, and a real sense of joy in the exploration and discovery of a new world. But it also has religious themes and a whole lot of human suffering, and it can get pretty painful at times.

In some ways the bones of the story could be an average Star Trek plot (first contact with less advanced aliens, two species of aliens sharing a planet with one being oppressed, human explorers accidentally interfere), but the level of emotional realism is way beyond most sci-fi stories, and it results in a pretty unique experience.