Some time ago, I watched James Tauber’s talk at DjangoCon about Pinax, a collection of re-usable Django applications. If you are thinking of a collection as a bunch of apps carelessly thrown together, you could not be more mistaken. Pinax is the foundation for a complete social networking site which covers most features you can imagine, the whole nine yards.
Forget django-admin.py startproject! Just do cp pinax myproject, remove some stuff you don’t need, adjust the templates and you are done!
Ok, I might be exagerating a bit, but watch the talk to build your own opinion.