I use the Sony Play Station 3, through a Schmartz SP3-IR1000, for Netflix. I think someone made a template for the Roku box also, but I've never tried it. It works just fine - LinuxMCE handles all the A/V routing automatically, so there is really not much to it when using it. You do need an Orbiter though - I use a DT tablet.
Netflix looks pretty sold on whatever fancy Microsoft platform they are using for web-clients. Last I heard, it doesn't even work outside of Internet Explorer. I haven't checked in a while, since all my systems are Linux anyway, and there is absolutely no Netflix support for Linux PCs.