Can anyone recommend a good open source document management system.

I want to manage my research documents.

I want a visitor to be able to view/download all my documents.
Index them hierarchically...etc

If a user has an account, then they can log in and post documents and possibly comments about them.

I was looking for a wiki type system, but not necessary....

Documents are mostly in odf and pdf.....

Any suggestions ?

I have tried Alfresco before, it seems the users are segregated with their own repositories, but can drop documents in the guest repository.

I was never able to change the guest page to display the repository.
Users had to navigate through the links on the guest page, avoiding the login prompt it seems.

I found dokuwiki, and it seems ok for now, but would like something thats stronger in the document handling area.
The wiki part seems ok.

The only things missing from dokuwiki are project tracking, as in attaching a tracker to certain topics, manipulating calendars and gantt charts....etc....

Currently I am looking at dokuwiki for results and agilefant for tracking.

I will ask again at the alfresco site if its possible, but alfresco doesn't seem as simple and neat as something like dokuwiki.

If you have any other suggestions, they are all welcome.