The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle have led to a re-evaluation of the physics potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal , the octant of , and the mass hierarchy, in addition to the measurements of , , and , for various combinations of -mode and -mode data-taking. With an exposure of protons-on-target, T2K can achieve 1 resolution of 0.050 (0.054) on and on for 100% (50%) neutrino beam mode running assuming and . T2K will have sensitivity to the CP-violating phase at 90% C.L. or better over a significant range. For example, if is maximal (i.e. ) the range is for normal hierarchy and for inverted hierarchy. When T2K data is combined with data from the NO A experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero is substantially increased compared to if each experiment is analyzed alone.