Apps to keep track of projects (areas, projects, to do, notes, files)?

Hi -

Does anyone have any suggestions for a single app to keep track of areas of responsibility, projects, notes, to dos, related files, etc.?

I checked out Things and Omnifocus, but they're more focused only on the to do portion. And this isn't really "project management" like Gantt charts and all that.

A single app that combines areas, projects, related to dos and sub to dos, related files (as links), related notes (such as meeting notes), maybe related people, etc. would be great.