Best database engine or access for F#?

After going through a couple blog articles on F# access to different database engines, I wondered what’s the best database engine/access for F#?

I use NHibernate and SQL Server on a daily basis from C#, so I naturally want to use NHibernate from F#. After some quick googl…research, I found this great article on how to setup F# to use NHibernate:
http://strangelights.com/blog/archive/2009/12/20/1650.aspx

I also came across an article on how to access MongoDB from F#:
http://codebetter.com/blogs/matthew.podwysocki/archive/2010/02/09/exploring-mongodb-with-f.aspx

After going through both and doing a couple quick spikes, MongoDB seems like a natural fit for F# and the functional way of life. Keep in mind, I’m new to functional programming and F#, so take this with a grain of salt and do your own research.

With F#’s parallel features, NoSQL database engines (MongoDB, CouchDB, etc) seem like a perfect fit. Large distributed data stores, asynchronous parallel processing, data stored as key/value pairs/objects, you get the picture.

It would be great to hear from anyone who’s used either with F# and your experiences. For now, I’m going to do some prototyping down both paths to see where what comes out the other side.