I like TiddlyWiki, and I like the d3 version for GTD, but it wasn't fitting how I wanted to organize tasks at work. The main problem, of course, is that my job doesn't fit GTD that well. Mainly that Done part. I always need to upgrade software to the latest version, and to fix something, and whatever: I have many eternal projects and loose tasks.
The real problem was that I was using Projects in d3 as Categories. So where do projects go? And so almost every action in some projects was floating, and that breaks down the utility of the powerful Next Action concept.
First I edited the GTDMenu tiddler, adding this line at the very top:
That line is just like the following line for Projects, except with Categories.
Then I created a tiddler titled CategoryList tagged gtd with these lines:
*<<list tagged "category -someday" all>>
*+++(gtdUncategorizedSliderState)[Uncategorized Projects:] <<list tagged "project -Category1 -Category2 -Category3" all>>===
Now make yourself some category tiddlers! Remember to use the category tag to make them show up in the menu on the left.