Write with the end in mind. That advice has been around for a pretty long time, I think, but it seems to me that in the writers' blogosphere, pantsers (a.k.a. people who don't outline) run amok, for various reasons: it's liberating to write without an outline; if you don't know where your plot's going, then neither will your readers be able to predict the plot. (Honestly, I'm not quire sure of the reasons. As you might've guessed, I'm not a pantser.)
But there's a reason, I believe, why "write with the end in mind" is valid advice. Every story needs a plot arc. If you know where your plot arc ends, you'll always have an end goal towards which you can work. It also saves you from wandering through your middle in one direction, only to realize that your story actually ends up over there -- and thereby rendering your first 10,000 words useless.
As an outliner, I like to go beyond figuring out the ending; I usually summarize the general events of my middle, too, so I always have a general idea of the scene I should be writing. But as long as you know where and how to bring your story to a close, I think you can go ahead and pants your way through the middle.
Do you follow this advice? Why or why not?