Honestly there much to choose from:
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Most of times it's ether you get good streaming options or great format support..
I know WD TV Live + is probably one of the few who do both, but I don't experience with it.
My netgear is ok, it does have rare issues with some of wagon mkvs, but for most part plays everything including dvd/bluray iso's with menu support, too bad br initiation takes over 2 minutes..
I'd consider Boxee Box the ideal device, but the noisy fan is a show stopper for me. Now, if you could relocated it into different room/sealed cabinet...
p.s: No more software media extenders for me