Out Of The Box
I always like using Out Of The Box features, pre-tested, reliable and quick to deploy and start using for the customer.
I've often wondered about this aspect of SharePoint, I know of the 40 or so Site Templates for SharePoint but that only scratches the surface about what could be done in this space. Lately I've been experimenting a bit with Office Live and it's very interesting to see the developments there (an example).
Last week MS published new Document Library templates for SharePoint that come pre-configured with appropriate templates. I'm particularly glad to see the use of Content Controls and how they link to the Document Library properties. From my perspective, just reading the .docx that come with the new templates is reason enough to spend some time investigating them and think about how you organisation could benefit from a similar approach.