If you take the time to convert your media to ATV2 .m4v format it'll stream on almost any wireless connection ~700MB per hour that's with DD5.1, plus the ATV2 will buffer to a degree. Try to use the 5GHz band as there's less interference albeit shorter range if you can.
We rarely buy physical media as our household viewing habits mostly single watch rentals of stuff we missed in the theaters. So we rent on iTunes for between $1 to $6 movies, dig for Netflix treasures at $8 month and purchase music for less than the physical CD in many cases. Media we own we've run through Handbrake (ATV2) or XLD (Apple Lossless) and save it in our library, the physical media is never touched again (an inspection of some of our older DVDs are showing small splits forming out from the center, glad we made a backup!). If a movie gets repeated viewings we buy & rip it, a process that takes about an hour per DVD on an older Quad core PC.
I've built a SageTV DVR to record all the network TV shows in HD as iTunes pricing on TV series currently sucks.
seems similar to what I'm doing. I learned today that I can only stream with the ATV when iTunes is running on a mac. Is this true? could I stream from the linux box I want to build?