1. A computing device, comprising: a touch screen display; one or more processors operative coupled with the touch screen display; memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs when executed by the one or more processors cause the device to perform: while a first application user interface is displayed on the touch screen display: detecting one or more first finger contacts on the first application user interface; applying a first set of heuristics to the one or more first finger contacts to determine a first command in the first application, wherein the first set of heuristics comprises: a vertical screen scrolling heuristic for determining that the one or more first finger contacts correspond to a one-dimensional vertical screen scrolling command rather than a two-dimensional screen translation command based on an angle of movement of a finger contact with respect to the touch screen display; and a two-dimension screen translation heuristic for determining that the one or more first finger contacts correspond to a two-dimensional screen translation command rather than the one-dimensional vertical screen scrolling command based on the angle of the movement of the first finger contact with respect to the touch screen display; and processing the first command; and while a second application user interface is displayed on the touch screen display: detecting one or more second finger contacts on the second application user interface; applying a second set of heuristics to the one or more second finger contacts to determine a second command in the second application, wherein: the second set of heuristics is different from the first set of heuristics, and the second set of heuristics comprises a next-item heuristic for determining that the one or more second finger contacts correspond to a command to transition from displaying a first element in a collection of elements to displaying a next element in the collection; and processing the second command.