Also useful for ordering tasks for a given day: e.g. at the start of a working day I want to pick 5 tasks that I *will* get done today, in order from 1 through 5 (or whatever number is appropriate.) These tasks might be chosen independently of their due dates or priorities, which is why an extra field is useful.

I upvoted this, but I thought I'd mention that there's a workaround already. Sort your list alphabetically, then edit the task names to start with .01., .02., etc. If you start it with a "." it rises to the top of the list. Use however many digits you think are in the highest number you'll use (so if you have 150 items you might go for ".001." If you don't then you'll get ".1.", ".10.", ".11." before ".2."

Not as nice or as easy to change on the fly as a separate field, but it works. It's how I do what you're talking about.

Great suggestion! I do this now by entering 1, 2, 3, etc. into the task name but what if I want to re-order the tasks? It falls apart.

This would also useful for purposes of grabbing a random task. Just go to random.org, have it generate a random number between 1 and 50, and do that task.