A function to log tri-axial accellerometer data to a text file on the hard disk, with system time, would be very awesome. Perhaps with options for the polling interval in preferences, with time in milliseconds or something?
So DarwiinRemote does this... sort of. It doesn't seem to allow you to change the poll time (which I *really* want) and it has some issues with the date (it just put 14:5:29 instead of 14:05:29) but my biggest complaint is that it only seems to log for a few minutes and then stops. :(