[support] Advise for new website

[Joe Java]

My company is looking to build an internal document/project/user
management website, perhaps using Drupal 7.
I would like some advise on module selection and site architecture.

There are 3 things the site needs to do.
1. Documents
A Document consists of a text file with many files associated with it.
Ex: legal document with a lot of images, specifications, videos, etc.
All the files will have tags associated with them for easy searching.

It is important that a user be able to download an entire document at
once (I think a zip file would work), or parts of a document,
say all images associated with a particular document.

2. Projects
A project is a group of documents, users on the project team, and
an organized drop-box of files that people can easily share.
A Drop-box is just a place to share files (they are not tagged,
but are organized by what directory they are in and  by their names).

Example of the drop-box structure is a directory structure like so:
project A
    legal
    specifications
    computations
    etc.
Project B
    plan sets
    proposals
    etc.

It is *VERY* important that user be able to move many files at once
into and out of the drop-box (entire directories or large sets of
chosen files).

I have looked but can not find any easy way in Drupal to move many
files back and forth between the client and server.  Multiple file
upload and download seems to be missing in Drupal core.
Ideally there should be a simple file drag and drop module for
moving files between client and server.

3. Users
Users consists of an email address an image and a bunch of meta data
(name, address, company, etc.)

Mailing lists are very important. Creating/deleting mailing lists and
adding/deleting users to the lists has be be easy.