Something I noticed with the Roku 2 and I might be wrong on this, I don't think it has DTS downmix, which means unless you have a dts capable receiver you're gonna downmix most of the bluray movies you backup through your computer otherwise you'll get no sound, unless of course you have a dts capable receiver then it shouldn't matter since you'll be using that instead.
Tiny new version of the Roku streamer. Rubbish for playing multi-format video, but these boxes are not designed for that. What they are good at is providing streamed content from the internet including Netflix. This new version uses a new Broadcom chipset (performance unknown).
IMO, Boxee looks like the best bet for everything you want.