If I had Air, I would store it in NAS or other computer with file sharing turned own. That way you can access them anywhere in your house and no need for cables
Does Apple have a recommended stand alone storage hard drive?
Interesting, I had NAS problems as well and gave up on that.
I think it constantly tries to read the files or something. I had only few movies on the NAS at some point and even that caused trouble.
My iTunes library, which I keep on my MBP, contains alias files for the real movie files, which are stored on a network drive. I discovered the hard way that I simply could not reliably stream those files to my Apple TV from my MBP. I solved it by syncing all of them to the Apple TVs own hard drive where they playback perfectly. Anyway, having the physical file(s) you intend to watch stored on the same device that is to replay them seems to be a necessity, in my setup at least.I tried an NAS, but I found that connecting to iTunes was unreliable over wireless. I keep all my content on my 27 inch iMac, and copy it locally as I watch it. If I do stream it across the network, it's my experience that it's much better coming from a shared iTunes library than a NAS.