I started using David Allen’s Getting Things Done system about two years ago. Like many GTD devotees, my adoption has been piecemeal. At it’s simplest, GTD is a clever way to organize life’s projects into the most minute of next actions. A project such as “Learn Italian” might have a next action “Order Rosetta Stone software.” That next action might have a context (where it’s done) “shopping.”

I’ve tried a few different ways of implementing GTD in my life. A Hanselminutes podcast turned me onto Moleskines. For a time, I used to carry one of these handy little notebooks around everywhere I went. But not surprisingly, a notebook is hard to keep organized. Such a system also works best when wearing cargo pants…

I gave the GTD Tiddly Wiki a try. I found it to be an effective tool, but it lacked portability (no mobile access). I’ve recently started using Monkey GTD for organizing work projects. I’m growing fond of it. But it’s still doesn’t have the mobility I want for managing my non-work life.

For about a year, I used an online service called Vitalist. This site, until recently, was by far my favorite way to implement GTD. Vitalist has a nice, uncluttered interface. It’s quick and responsive (typical AJAX-y site). It has a nice feature that allows reminders (at custom times) to be sent via SMS or email. There’s a sharing feature to allow some basic collaboration.

I grew more attached to Vitalist when I got my Motorola Q. Vitalist has a pretty usable mobile site. Mobile Vitalist got me back to the portability I enjoyed with the Moleskine, but was much easier to keep organized. After I got my iPhone, I continued to use Vitalist. But there was something about having an iPhone and having to use a web app built for any mobile phone that juts didn’t feel right.

A couple of months ago a coworker introduced me to Things, by Cultured Code. Things is a desktop app for Mac OSX and for the iPhone. This app is brilliant. It’s simple and intuitive. It has an incredibly feature complete GTD implementation. The mobile app seamlessly syncs with the desktop app over your wireless network. Things nailed navigation. It’s amazingly simple to add a next action, whether to the Inbox, to a project or any other GTD standard location. Actions may be given a due date, starred or tagged or just left in the inbox for later processing. Things got it right.

Since installing Things, I’ve realized there are certain types of software that simply don’t work as well on the Web. Task management and calendaring are two such apps. Even with a bookmark to Vitalist’s mobile site on my iPhone’s homescreen, there was a lack of immediacy to allow it to be truly effective. Having to load Safari, occasionally login and then navigate the site was too cumbersome. Reviewing and adding next actions needs to be fast and extremely convenient.

I use Things most often while on the train commuting to and from work. Having the iPhone client allows me to manage my actions even when under Grand Central and without access to a data network. The badge option (turned off by default) allows Things to show a little red circle on the app’s icon. The circle contains the number of items due for the day. I find this is a much better reminder tool than email. Vitalist’s reminders started to add to my email noise and I started to ignore them. The badge greets me whenever I look at my phone’s homescreen.

Things has already made me more productive. Vitalist had a similar effect early on as well. But the sheer number of next actions I’ve already pushed through Things is more impressive to me. And of course, while writing this post, I added a next-action to put it online when I am off the train…