I found an interesting alternative data access layer (DAL) to NHibernate called SubSonic.  It was formerly called "ActionPack", but I guess there must be enough confusion with Microsoft's "Action Pack" that they changed the name.  SubSonic is open-source (MPL)

SubSonic has been hailed as "Ruby on Rails" for .NET developers.  There is a screencast of it here, prepare to be amazed.  It works kind of like this:

1) Add a reference to the SubSonic DLL
2) Modify your web.config with connection string info and SubSonic build provider info
3) Build the project
4) ...
Copyright (C) Sidney Harris.

5) Amazing!  Domain objects and data access layer have been automagically created!

I foresee this as a great way to quickly get a data-driven site up with a minimum of development effort.  Realizing this is not the end-all and be-all of data access, you are still free to use "traditional" ADO.NET techniques.  A recent benefit is that CodePlex has come out with an XmlProvider, so that if you would rather persist to XML instead of a database, it can handle that data access layer, too.  This thing keeps getting better and better.