I organise. It's heritable, too; my mother is a world grand-master list-maker who taught me, among other things, how to use the backs of envelopes to survive paper shortages (which pose a serious psychological risk to list-makers) and save the planet at the same time (list-makers love killing two birds with one stone).
Through my life, I've met a few others like me, most notably my friend Jennie with whom I sat back to back during grad school. She and I fanned the flames of each other's list-mania and to this day we exchange new and improved ways of making, keeping and organising our lists.
And oh boy, do I need my lists. I've got
my country's Charles Darwin's
five two hundredth anniversary to plan, my
wedding Beagle Project science programme to arrange, my
wife research to
murder publish,
and Guilder to frame for it. I'm swamped. (If you're really confused right now, stop reading this and go watch
The Princess Bride.)
I've tried a few different organising systems, including but not limited to:
This year, though, I think I've finally hit on a winner: a combination of iCal (especially using the File > New To Do function) and Moleskine's Weekly Notebook. Nearly halfway through 2008, it's working really well.

I really like how the calendar is on the left hand side of the opened diary, and on the right there is a simple ruled page to jot down notes (that way your notes are instantly traceable by date). I love my Moleskine, and I look forward (as all list-makers do) to the end of the year when I can start with a shiny new Moleskine with fresh, clean pages.
Problem is, I'm already starting to accumulate things for 2009 and my Moleskine ends in December. What to do? I turn to the last page and keep a list (I'm so predictable) of things that will have to go into my 2009 Moleskine. It's not very satisfying but at least I know I won't forget anything important.
You can imagine my delight then when I found in my in-box an email from UK online Moleskine dealer
MojoLondon that Moleskine is now selling
18-month diaries that start in July and go through the end of the following year. That means I can start my clean and shiny new Moleskine
this July ...a mere four weeks away. And here I thought I had to wait until Christmas.
The big decision is whether to get the
Large Weekly Notebook Hard Cover or the
Extra Large Weekly Notebook Soft Cover. What a lovely decision to have to make. I think I'll go put it on my to-do list for tomorrow.
Update, 2 June 08: Lacy has discovered an
even better way to make sure you don't forget any of those important t0-dos.