I also use Mezzmo (running on a Windows Home Server box) with my UN46B7100. I used Twonky Server for a few months until they dropped the WHS version. Looked at Tversity and others, but Mezzmo was the best I could find. Nice GUI, smart playlists - essentially you can arrange your media pretty much how you want to, thumbnails for videos etc.
For anyone interested in setting up DLNA servers with their Samsung LED TV's I thought I'd post the following to save others wasted time..
I initially looked at the free version of TVersity, the functionality seemed fine however for some reason (whether it be Samsung or TVersity) the Samsung TV does not detect the DLNA server. I tried absolutely everything from editing profile.xml pages etc..
However I looked a little more into DLNA servers and found a product called Mezzmo (http://www.conceiva.com/products/mezzmo/default.asp) by Conceiva. This is certified to work with Samsung unlike TVersity and did exactly that, my Samsung LED TV picked it up straight away. Some might say .. Samsung provide a DLNA server with the TV - I did look at this but it really has only basic functionality.
Mezzmo on the other hand can transcode on the fly for those videos that wont play and also has full media library functionality to organise your films, music and photos. I have found my trial version great and will purchase the full version.
My wife loves the fact that she can now find our thousands of photos with ease i.e. Brothers Wedding or pics of my daughter - before she had to work out the month of the photos being taken to find them on a normal Windows file system.
My opinion, dont waste time getting DLNA servers working with Samsung unless they truely support Samsung TVs - I had wasted so much time when all I had to do was install Mezzmo!
Samsung LED TV 7000 Series Owner