In thin films, lamellae self-assemble primarily parallel to the film interface with the lamellar width determined by the molecular weight of the block copolymer and the grain shape determined by the coil fraction. In symmetric block copolymers, in-plane lamellae grow in irregular polygon grains with linear sides defined by defect lamellae oriented perpendicular to the film surface. However, as coil fraction is increased the polymers transition to a regime characterized by regularly-shaped square grains. With varying film thickness, rod-coil block copolymers form islands and holes due to a dimensional mismatch between the characteristic dimension of the block copolymer and the thickness of the film. In films less than several lamellar layers thick, unusual three level island and hole formation may also be observed. Increasing film thickness results in reorientation of the lamellar structures at the air interface, and for thick films all of the lamellar microdomains are oriented perpendicular to the air interface. This reorientation is localized near the air interface, indicating that the orienting effect of the substrate has a limited range through the film. In coil-rich polymers, large islands and holes form in films with reoriented surfaces despite the lack of a characteristic block copolymer length in this dimension, suggesting that kinetic effects play a large role in the formation of these morphologies.