I have been used to try and drop off many software and technics to organise my workflow. It is a kind of obsession that I document, I might end by writing something about it someday.

The new software I use: workflowy chrome app

And so far… I love its simplicity & user interface!
[youtube https://www.youtube.com/watch?v=CSmbnaPZVHE?rel=0&w=960&h=720]

The last one I used was http://www.actionmethod.com/product/online. I choosed after testing The list of the Retro-Planning Softwares I tested:
https://www.zoho.com/projects/
http://www.projectmanager.com/
http://www.easyprojects.net/
http://www.unmariageaorganiser.com/ (Yes I tested wedding planning tools)
http://www.missorganisator.com/fre/5/outils

[EDIT, 2014.08.12] If I don’t stick to workflowy, here is an alternative http://www.omnigroup.com/omnifocus/