I'd just love to see a solid open-source standard graphing calculator app for the common tablets - something like a more user-friendly version of gnu octave or something. The vendor lock-in by the education industry and TI is absurd.
Seriously, the few times a month I need to crunch numbers I reach for my phone, then get frustrated and just use Google because my TI83's batteries have been dead for years. I don't know what it is but I haven't seen a touch calculator interface anywhere near as good as a standard graphing calculator for just banging out some computations.