For GTD, I generally like apps that have a good desktop companion. The desktop is more convenient for heavy data entry. My main GTD tools are DateBk5 and Bonsai. Other useful apps are:
- TurboPasswords: Good desktop companion that integrates with IE6. It
automatically fills in user name and password on web forms. A great time
saver for all the web based tools I use for work.
- Palmary Clock: alarms, timers, stop watch
- NeoCal: Good RPN calculator
- Documents to Go
- Various utilites: 5N Launch, FileZ, Uninstall Manager, Crash,
BackupBuddy VFS & Icon Manager
- Assorted games when it's time for a break.