I am a devoted outliner. I've only ever managed to finish one novel without an outline, and that was the first one I wrote way back in my early teens, and it was really, *really* bad. (In part because I had no idea what I was doing, but the lack of outline didn't help anything.)
But of course, every novel is a little different, particularly in the journey *to* the outline.
The last novel I finished (which I'm actually working on the third draft of right now) was different from the others in that it's based on Norse mythology. So I had a sort of outline already in place--certain characters and events in a certain order that were already established.
As soon as I got the idea, as always, there was much jotting down of notes and considering who my (non-mythological) main character could be and what his motivations were and all that. Many pages of notebooks filled.
Once I had a decent idea of all that, I made a list of the mythological events I wanted to use, in their approximate chronological order (approximate because Norse myths get a little hazy with the chronology here and there). I also re-read my main sources for the myths and some other reference books on the mythology and culture both for inspiration (sometimes research can give you the perfect answer to some question you haven't been able to answer, just out of nowhere! I love research) and to make sure I wasn't mucking things up too much. ;)
Then I figured out how my main character would be involved in the mythological events, and how his goals and efforts to meet them would fit around them. And that's when I wrote my outline.
Unfortunately, the first outline didn't work out so well. (This is why I outline. It lets me test-drive ideas to make sure they're ready!) So I let it sit and stewed over it and wrote a couple other books and finally came back to it and figured out something important about the main character that made the pieces come together properly, and then I wrote the real outline, the one that let me write the first draft.
(For the curious, I outline on index cards, scene-by-scene, with several point form notes on each about the important events in that chapter, and any details about character development/foreshadowing/world-building/e
I outline each draft after the rough draft, too. The current draft actually required quite a bit of outlining because I was making a few major plot changes and needed to figure out how to work them in with the stuff I was keeping from the previous draft. I find it really hard to work out the big picture stuff while I'm actually writing/rewriting/revising which is why I turn to outlining so often.
So yeah. I am the Outline Queen! :D