Decisions, Decisions

Everybody knows there aren't enough hours in the day. Just now I was faced with deciding between emailing a bunch of friends I've ignored for far too long, revising an article a friend is waiting for, or blogging. And that set of choices only had to do with this hour; my whole evening has been a series of multiple choice questions like this. Part of the problem is that selecting any one of these options causes me to further put off addressing the other options.
So do you live life organically, deciding what "wants & shoulds" to focus on at any given moment? Or do you apply some kind of structure to discretionary time, writing at 7PM on Tuesday because 7PM on Tuesday is when it is time to write? What if you don't want to write at 7PM on Tuesday? What if you don't find the time to do the writing you want because you didn't set aside time for it at 7PM on Tuesday?
In part, it's about balance. Leaving some "white space" in your day while having the discipline to do important things without waiting for inspiration to show up. It's also about making peace with the fact that you can only do one thing at a time and some things aren't going to be done at the end of the day. So with apologies to my friends waiting for emails, I'm going to go work on that article now.