"1:1" educational computing refers to a scenario where every student in a group or class uses a computing device equipped with wireless communication capability to conduct a learning task. This paper, drawing from design experiences with our digital classroom environment series and other studies, attempts to describe a few valuable "1:1" design perspectives for educational computing inside the classroom. We try to describe the major components of the "1:1" digital classroom environment and classify the most important component, student devices, according to a set of features. Furthermore, based on the notion of computing affordance, a set of communication affordances are described. This set underpins three basic educational activities, namely: teacher-directed instruction, small group learning and individual learning. Finally, scenarios are exemplified for a few typical educational computing devices. This study concludes with a discussion of short- and long-term research possibilities.