I've used a number of task list managers throughout the years, some graphical and some on the shell. Taskwarrior seems like a great tool (from the testing I just did on it).
I use Remember the Milk and will continue using it, as it works on desktops, tablets and phones, family members also use it, and we make heavy use of shared lists.
If issue http://taskwarrior.org/issues/129 is ever implemented, I might start using this as a shell back end for RTM (which would be awesome).