I've been playing around with my Oppo BDP-93 to try to get it to stream media on my network. I tried installing the Plex Media Server (Nine), but the Oppo would not see it, due to Plex Nine not supporting UPnP anymore. I then tried XBMC, which the Oppo easily discovered, but it took some work figuring out how to get the media to show up and play. Building the library did not work as nicely as Plex Nine did.
I next tried Plex Eight, as it still had UPnP support. The Oppo could see that, and I could get it to see some of the media files (the nice building of the library only came about in Nine), but the ones it could see would not play - it may have been a codec issue, as I tried different media each time.
I've been pondering different media streaming hardware, such as the Boxee Box and the LG ST600 Smart TV Upgrader, but have been feeling hesitant on those. It turns out that Plex now has a Roku app so network media streaming would be possible there, as well as use the most recent Plex Media Server, so I am pondering that now. In addition, Plex just released their Plex Media Server for Linux. It's still in Beta, but I am glad they are getting there, as I would prefer to have it run on my Linux box as opposed to my Mac (where it now sits).