Whether it's a command, or custom snippet, or some other form of text completion, possibly tied to a key binding, I REALLY REALLY would like to be able to Insert Date (and I suspect others might want to go further and insert time, possibly even format the inserted date and/or time).   With TextMate, there was a Auto-Completion code setup (in TEXT category I think)  isoD (tab) automatically inserted the Date in ISO format - that would be a great start!