That, to me, is one of the defining features of a general-purpose computer. Can I develop software for it, with it?
Perhaps it might not be pleasant, if the hardware isn't very powerful - looking at 20 lines of code on a netbook screen, or waiting for the serial communication to catch up to my terminal on the embedded board - but it makes it a tool with which you can do real work. Tablets and phones don't count yet.
Edit: Yes, I am aware of the SSH clients, with which you can connect to a remote server, do the development there, and download the resulting app. But the remote server is the general-like computer there, just as the PC running the terminal is not the primary machine in some embedded development.
Seriously. The only thing keeping me from trying out an ipad is the inability to install my own software on it.
Until then, 10-11" chromebooks are scratching that itch for me. They usually have 360-degree flip keyboards with touch screens, and they'll run a full ARM Linux stack with dev mode on. Plus, the UI and Android app support are great.
