We're compiling a comprehensive list of all GTD list manager apps - please help us make sure we're not forgetting any! List any you know of for any platform.
Mac OS X
The Hit List
OmniFocus
Things
Midnight Inbox
TaskPaper
Chandler
What's Next
Evernote
Task
Windows
NetCentrics Outlook Add-In
ClearContext Outlook Add-in
Task Tiger (beta)
MyLifeOrganized
Actiontastic
EasyTask Manager
eProductivity for Lotus Notes
Evernote
FusionDesk
Tudumo
Web Apps
Vitalist
Toodledo
Tadalists
Nozbe
Tracks
SimpleGTD
Mojonote
Tasktoy
Todoist
Remember the Milk
Evernote
iPhone
To Do
DoBot ToDos
Todo
Get It Done
Things
Nozbe
Omnifocus
Action Lists
Nubi Do
Task PRO
eTodo
TaskTrail
Toodledo
2Do
Done
Ultimate Todos
To-Do List
Milpon"
Remember the Milk
EasyTask Manager
Evernote
Android
Shuffle
ActionComplete
GTD Agenda
Palm
Blackberry
NextAction!
ToDoMatrix
Evernote
Role Call
Windows Mobile
NextAction!
SPBDiary
MyLifeOrganized
Symbian S60 / Java
SBSH Calendar (formerly Papyrus)
Projekt
Mobile Task Manager
Active Notes
Mac OS X
The Hit List
OmniFocus
Things
Midnight Inbox
TaskPaper
Chandler
What's Next
Evernote
Task
Windows
NetCentrics Outlook Add-In
ClearContext Outlook Add-in
Task Tiger (beta)
MyLifeOrganized
Actiontastic
EasyTask Manager
eProductivity for Lotus Notes
Evernote
FusionDesk
Tudumo
Web Apps
Vitalist
Toodledo
Tadalists
Nozbe
Tracks
SimpleGTD
Mojonote
Tasktoy
Todoist
Remember the Milk
Evernote
iPhone
To Do
DoBot ToDos
Todo
Get It Done
Things
Nozbe
Omnifocus
Action Lists
Nubi Do
Task PRO
eTodo
TaskTrail
Toodledo
2Do
Done
Ultimate Todos
To-Do List
Milpon"
Remember the Milk
EasyTask Manager
Evernote
Android
Shuffle
ActionComplete
GTD Agenda
Palm
Blackberry
NextAction!
ToDoMatrix
Evernote
Role Call
Windows Mobile
NextAction!
SPBDiary
MyLifeOrganized
Symbian S60 / Java
SBSH Calendar (formerly Papyrus)
Projekt
Mobile Task Manager
Active Notes