A quiver of tools
I long ago came to the conclusion that projects vary so much in size and scope that there is no one tool that is effective and efficient for all of them. I've adopted a collection of tools and use the particular tool that best fits the requirements of a particular project. If you managed large, multi-month construction projects, for example, and had to coordinate the efforts of multiple teams and crews of workers, and bring the project to completion on schedule and within budget, you would likely live in something like Microsoft's Project. Even so, you would likely have a number of other projects for which Project would be overkill. You might find the Netcentrics GTD Add-in perfectly suitable for many or most of those.
I don't want to paraphrase him here, but my interpretation from some of his podcasts is that David Allen has said essentially the same thing multiple times.
I've used quite a number of PIMs over the years and there are a number of excellent ones available; some of them with much more powerful project planning capabilities than Outlook. But since e-mail has become such an essential communication medium, I find Outlook--an e-mail client--to be the logical choice for the core of a system. It plays nicely with the other Office applications (including OneNote and Project) and since it's the industry standard, other useful productivity apps and plug-ins are designed to work with Outlook.
I must have been one of the very earliest purchasers of the Netcentrics GTD Add-in but dropped it in favor of other tools with stronger Project capabilities. Now, with version 3, I am back to using it again and it is becoming my official Projects list. It's all I need for many projects. I find it especially well suited for projects that involve a lot of communications. For a real estate transaction I'm involved in, for example, that's generating a lot of e-mail messages and notes of telephone conversations.
Another project is a web site rebuild that involves relatively little communication but a lot of information. It's set up in the GTD Add-in too, but it also has its own OneNote notebook and that's where I spend most of my web-site-rebuild working time. I especially like the ease with which I can quickly build an Outline in OneNote and then flag any to open up as an Outlook task, which can then be assigned to a Netcentrics GTD project and subproject. I don't bother doing so for most discrete tasks, but I will if I want it to appear in Outlooks task lists or block out some time on the calendar for it.
I have MS Project but could never justify the overhead of maintaining the system for the kinds of projects I'm engaged in. Once in a while, though, I find it useful to track a Gantt-chart timeline and budget and I use JCV Gantt for that.
If you're looking for something that will give you a multi-level tree structure for organizing project tasks, you might consider Franklin Covey's Projects Plus add-in for Outlook. It's the project planning component of their PlanPlus suite and with a much lighter footprint than the full suite. You could use it for most of your project task planning and still assign tasks to the GTD projects and sub-projects. I've encountered no problems running it on a laptop together with the GTD Add-in and Outlook 2010 beta. I think it's only $30 or so and I believe they offer a free 30-day trial.
