SE has a fairly good keyboard shortcut system. It's served me fairly well during this period of me not being able to left-click anything. You can navigate to /questions, /users, meta, the tour... etc.
One thing that seems to be missing, though, is a keyboard shortcut to /questions/ask. This is an important page, and it's a bit inconvenient to have to go tabbing through the page to find it (or manually typing it in the URL bar).
I'd suggest that the keyboard shortcut, to be consistent with the other ones, be G and then A. No other keyboard shortcut is currently using the A key, and it seems a logical choice for "ask".
And, of course, don't forget to add it to the auto-help ;)