Forms Authentication, Identities and Roles from a Database:

One of the most useful and perhaps most misunderstood authentication schemes built in to the ASP.NET runtime is Forms Authentication. Useful, because it is highly extensible and flexible (as we'll see in a moment). Misunderstood, because most developers don't get past the default setup described in the documentation and therefore never find out how to extend and customize it.

I still don't understand why I have to roll my own Forms auth with Roles, I would expect that everyone would want to use roles, but oh well...