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!
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:
http://www.unmariageaorganiser.com/ (Yes I tested wedding planning tools)
[EDIT, 2014.08.12] If I don’t stick to workflowy, here is an alternative http://www.omnigroup.com/omnifocus/