I used Airvideo for a while, but as you state it streams through your mac which is a bit of a pain. Also I had constant problems with the Airvideo server on the mac. I have now deleted Airvideo and use Airplayer which you can stream to from your ReadyNas. It seems to handle many video formats and mp3 too and even my music in Apple Lossless format.
NAS: Readynas Pro 6 - 3x2TB [ST32000542AS], ReadyNas Duo - 2x1TB [ST31000528AS]
Network: Airport Extreme [Gigabit Ethernet / Wireless], Western Digital 2TB, Virgin Media Super Hub [30Mbps]
Hardware: 24" iMac, 13" MacBook, 11" MacBook Air, 2 x Apple TV2's, iPad 1, iPhone 3G
Clients: OSX 10.7.2, IOS 5.0/4.3, Plex 9.3.4
Music: 1 x Logitech SqueezeBox Classic, 2 x Logitech SqueezeBox Boom's, M-Audio Oxygen 88, Apogee Duet 2
Software: Adobe CS4, Aperture 3.2, Guitar Pro 6, Logic Pro 9, Vectorworks 2009