I mostly use small 3rd party django apps that provide discrete pieces of functionality. sorl-thumbnail or django-mptt, for example, don't provide any views, they are helpers to provide dynamic thumbnailing and tree-operations to existing models.

I do use a few more "stand-alone" apps (like django-filebrowser and the basic-apps suite) but I tend not to use apps that provide a ton of functionality or try to run the whole site. I used to have only one exception to this rule (satchmo, about which I'll have more to say in the future) but I recently added a second exception.

If you need a simple standalone helpdesk, Jutda Helpdesk is your one stop shop. Recently I needed a workflow with a particular client that had more structure than CC'ed emails or even basecamp todos. Jutda worked out of the box (after a couple of one-line fixes, patches for which were immediately accepted and applied) and provides an interface for users to report issues, admins to assign them and everybody to get email notifications as status changes occur.

This is a substantial project (there are features I didn't explore like ticket creation from an email inbox, an API and customizable RSS feeds) which just works. My compliments to Ross Poulton!