The Hit List from Potion Factory is a beautiful new application that immediately competes with Things from Cultured Code and OmniFocus from The Omni Group.
The Hit List has one of the most beautiful icons I have ever seen and fits in perfectly with your Mac desktop.
It is somewhat along the lines of Things and OmniFocus in that it roughly follows the GTD philosophy, where tasks are divided into different groups based on their timeframe, project, and context. Like OmniFocus, tasks are shown in an outline view, but it looks more like ruled paper.
Here is a full screenshot:
One really interesting feature is the built-in time-tracker, which allows you to show both elapsed time on a task and ETA (as set by the user for the specific task).
Overall, the software appears to be much more flexible than Things (I haven’t had a lot of experience with OmniFocus; it was too complicated for me). It certainly, at least to me, is far more visually appealing.
There are a few problems, though, but this is a private beta. I received errors when I attempted to add a sub-task to another. Also, the functionality to synchronise with iCal seemed to be disabled. I have not tested it extensively for bugs, because, as I point out in the next paragraph, I won’t be able to use the software in the long run.
Unfortunately, all this comes with a rather large price-tag: $69.00. While I am all for independent software developers making what they deserve (and they certainly deserve all they can get), I am unable to afford software like this. So, while it is incredibly beautiful, I will not be able to use it beyond the beta period, which saddens me.
To conclude, applications like The Hit List are what get me really excited about living in the Mac platform. Here, beauty and utility go hand in hand, though it come at great monetary cost. When I used Linux, often an application would include a poor-to-mediocre user interface (of course, never integrating with the rest of my software because of the multitude of interface kits) and limited-to-high utility; occasionally, the user interface would be nice, but the utility would be almost nonexistent, and the software would be really, really buggy. When I used Windows XP, usually the utility was limited-to-medium and user experience very, very low (except for pro apps like Adobe CS3).
Every time I start to get a little worried about the decadence of the Mac community, something great like this pops up and reminds me why I spent all my money in order to join it.

23 December 2008 at 7:05 am
For implementing GTD you can use this web-based application:
http://www.Gtdagenda.com
You can use it to manage your goals, projects and tasks, set next actions and contexts, use checklists, schedules and a calendar.
A mobile version is available too.