I've scoured the Internet trying to find software that can do the following: in one interface, group emails, files, tasks, notes, and calendars into folders and sub-folders.
For example, I want to create a folder called 'Studies' and be able to see all emails, notes, tasks, lists, etc. under that folder.
I'm trying out Toodledo and it does provide the function of grouping tasks, lists, notes under folders, but it doesn't provide integration for email and calendar events.
If Outlook Express or Thunderbird have add-ons for these type of functions, that might suffice too.
I'd prefer a Ubuntu-based solution, but if none exists, then can consider a Windows solution.