Python or PyPy for small group and large project?
HTML 5, CSS 3 - PyPy 1.4/CPython 3 + Pylons/Tornado/Django - CouchDB/MongoDB/Riak + Erlang?

Simplify.
Python 2.7, Django 1.2, SQLite and MongoDB  get started building stuff right away.
Add later.  Upgrade to Python 3 later.
Early stage of planning a large project - difficult decision of choosing frameworks :)
In mind:

"select way - run fast".
 Select technologies with growth opportunity, prototype as fast as possible.
"look at horizon - build a ship".
 Understand the scope, invest in difficult decision but reach the goal.
"take the best - enjoy the ride".
 Bring the best team, do not let them fall aboard.

Choose from:
HTML 5, CSS 3 - PyPy 1.4/CPython 3 + Pylons/Tornado/Django - CouchDB/MongoDB/Riak + Erlang?
First step: 3-4 developers in team + 1 admins + 1 designer.
Designer - View + Service Developers - Admin - Balance + Structure Developers
Second step: 5-7 developers in team + 2-3 admins + 1-2 designer.
Updated: Python + Pyramid (Pylons) + Couchbase (CouchDB)