I've been using TwonkyMedia to stream video and MP3s to my Xbox 360 for at least 6 months now from my Synology 106j. All has been well but I was never able to stream WMV despite support.
However I have just retrieved my Xbox back from my brother (who stole it for 2 months) and after installing the latest dashboard update I can successfully say that it is now capable of streaming DivX etc using software version 4.4
So now I can sack off my old Xbox and XBMC which has done me soo well all these years. Finally I have a full download/media solution using only 2 bits of hardware and without a single pc.
Only thing I have noticed is that now and then the xbox seems to loose connectivity whilst streaming mp3 files, which it never did on the previous dash. But I think that could be cause Im canning it at the moment