Williams and Mattingley have done an elegant study (Current Biology, vol. 16, pp 402-404, June 2006) that demonstrates that men detect angry male faces significantly more rapidly than women do. On the other hand, women are faster a picking out a happy, sad, surprised or disgusted face. The addition of neutral distractor faces to the search display has little effect on the detection of angry male faces by either male or female observers.
A brief quote from the beginning of their article give the context and importance of their observations: "In humans, evolution has resulted in marked differentiation between males and females, including differences in the structural and functional organization of the brain. These differences are reflected in patterns of cognitive and behavioural abilities. For example, females tend to perform better than males at fine motor and perceptual discrimination tasks, whereas males are better at route-finding tasks. Males are also physically larger and more aggressive than females, and so more likely to pose a physical threat. Such physical differences between the sexes may in turn have shaped the cognitive processes involved in detecting threatening behaviour in others. Early detection of an angry facial expression, for example, might reduce the likelihood of an injurious or potentially fatal confrontation. Similarly, detection of a fearful expression might warn of a potential threat in the immediate vicinity. Although much emphasis has been placed on such cognitive and physical distinctions between the sexes, few studies have investigated differences in the efficiency with which males and females perceive facial expressions, despite the potential importance of affect perception for survival......From an evolutionary perspective, the potential for physical threat from a male is greater than that from a female. A perceptual system that prioritizes detection of angry male faces, which directly signal potential threat, is therefore likely to be advantageous."