A few months ago, I finally got fed up enough with my non-existent organizational system that I went hunting around for a new approach. I'd previously used an HP iPAQ Pocket PC - until it died a sudden and unexpected death - and then I was without a handheld device other than my cell phone, which had my contacts in it but that's about it. So after finding the Blackberry Pearl (which I used until recently when I dropped it one too many times) I was set on the calendar and contacts fronts because I sync these features with my work Exchange server. The task manager was more of a problem. I absolutely abhor Outlook's task manager, and despite several attempts to use it in various ways, I've given up in exasperation.
My biggest challenge, in my work and my life, has always been remembering everything I need to do. I recently learned about David Allen's Getting Things Done approach and after reading (most of) his book (err, oops?), doing some research and poking around online I decided to try using a pocket-sized, squared Moleskine notebook together with padded (i.e. sticky, like post-its) blank 3x5 cards and some repositionable index tabs. My system looks sort of like this one. (I can't find the page for the actual system I've been using, alas, but I'm cruising through the Getting Things Done pool on Flickr and am getting more ideas!)
Anyway, after using this system for just a little while, I fell in love with these notebooks. I absolutely adore them. They are the perfect size, lay flat when you open them, the paper is soft and silky but not super-thin, and they come in such a wide variety of sizes and styles everyone is sure to find at least one to tickle their fancy! I currently am using the pocket-sized squared notebook for my personal To-Dos, a larger, journal-sized squared notebook for all work-related items, and a third, lined journal-size notebook as my regular journal - it stays by my bed and gets written in when the topic of my journaling is not blog-appropriate. :)
I've found these notebooks at a variety of places: Amazon.com seems to have them for the cheapest price, but I've found them at bookstores like Powell's Books (for those of you within driving distance of Portland, OR), Borders and other book stores. I imagine art supply stores might also carry them.
(And for what it's worth: I've found the Getting Things Done approach to be really helpful, when I use it. And the point is, you have to use it. The challenge for me, with my work and life in general, is that tasks seem to generate themselves and while I should be furiously writing them down as they come to me, I usually don't even have a spare second to do so because of deadlines and etc. So I'm still tweaking the system to best work for me and am trying to get into the habit of getting out the notebook as ideas come to me.)