Say I have a Visual studio solution with two projects: one web project, and one data project.
Does it really matter whether I pass the EF object from the data project to the web project, or do I need to explicitly define POCOs in the data project to pass to the web project?
It seems to me that needing to create POCOs instead of simply using EF objects adds yet another thing that needs to be done...and I don't particularly see the purpose.
If you're using Entity Framework 4, the EF objects are POCO objects, and so should be used in any situation where your Model matches your EF object (CRUD operations are the typical ones). However there will more than likely be situations whereby the standard POCO object doesn't encapsulate all of the fields that are needed for a View Model (typical ones I have this with are account pages where you have two password fields) and so you will need to create a Model for the page, which then passes the data into your EF POCO objects.
So if you're using DbContext (which creates POCO objects for you) there is no reason not to use those objects.