IMO any form of USB is not the greatest thing for major file xfers and streaming videos. Yes USB has it's place however USB can really only do so much. And depending upon the attached devices and there performance and designs and how they are Mfrd, can also have am impact on many things for USB.
Honestly, however, your trying to use USB to stream and to major xfers in which there are better alternatives. IMO, if your going to be doing this kind of thing, you really need to get on the Gb LAN wagon and use that as your main forum of streaming and xfers. USB just can't hold a candle to Wired LAN connections. Only thing I use on USB is some small xfers I need from my external drives for back up, I/O functions and testing USB printers when needed. Surf, email and such wireless when I'm on my LT. Most everything I do is Wired LAN. Less hassle, FASTER, and better stability. I have a server thats wired GB to a switch and a USB and Firewire drives connected to the server and shared for storage. All my other PCs and Boxee Box is wired in to the switch for seamless networking and no interferences or performance hits from the my host router. Which is another reason to go wired and get a network switch. Yes these routers should handle most anything however in my experience that having a switch in the mix greatly helps connections between devices, less router processing and management, allows the router to do just that, route traffic when needed and provide internet, in stead of having to deal with it ALL the time. Allows connected devices between each other to have a connection with out any processing from the host router and best of all, connections speeds and file xfer speeds are only limited by each devices, not by the router or a non LAN connection.
So when I'm watching boxee streaming full raw media files from the server, I can game or someone else can surf or do other streaming from the web with out any interferences seen on the boxee. This is the job of the external switch.
I would highly recommend you review your situation and see if you can use wired LAN as your solution.
My 2 cents.