The backend PC doesn't need to be that strong of a system. I'm using an Athlon 64 X2 4000+ (2.1GHz 65W) cpu in a linux box running software raid 5 (5 320GB drives) shared via Samba. The video playback machine is an Athlon 64 X2 5200+ (2.6GHz) using a Zalman CPU cooler and a GeForce 7950GT fanless video card. This PC was build around Nov 06'. The CPU isn't up to playing downloaded HD content when I'm running at 1080i but it works great at 720p. If I was building today I would get a 3GHz socket 775 Core2 Duo and for the video I would get something from this selection. I'm running Windows XP on this PC and Zoomplayer to play DVD's using the Nvidia PureVideo codec. I also run AnyDVD to skip directly to the DVD menu when inserting a DVD. I have read that PowerDVD is the best option for PC BlueRay playback but I don't have a BlueRay drive in the PC.