Get to know linux well before you deploy it. I ran my own A/V install company from 2003 - 2007 and I know how testy those darn customers can be. Myself, a person with a decade of linux experience recently ejected linux from my a/v system and scaled back to desktop and other uses. I am a CEDIA CCPI1.
I use a NAS server from Synology to suffice for one stream at a time. I can do more depending on the bit rate. While I had a Zotac ION dual core board with a SSD as a "net top" front end the topic of troubleshooting exactly why my movies would start to stutter roughly one hour in was not a trivial effort. I would hate to see an av guy in a persons home for the length of time it would take to figure that one out. That and your customer would be less than happy I am sure. Three RMA's came out of that as not one person at tech support for the Seagate drives, the OCZ memory or the Supertalent SSD drive would say their hardware was not at fault.
I cleaned house going for Western Digital Caviar Blacks in a raid array for the NAS server and moved my front end over to Apple hardware. Apple is about the only company that will stand behind both the hardware and the software. Call them with a problem and you either get a local appointment or a shipping box will be on your doorstep in one day, most cases.
The mac mini is the ideal front end. Built in: IR receiver, 802.11N, dvd drive, and excellent scripting. Heck I just add in to the startup items to sign in to the NAS server and to open XBMC. Had to get a mini dvi to hdmi for an HDMI cable. That and I bought an M-Audio transit as the framework for the optical/ mini stereo port was supported only by description. The Maudio transit is a usb to toslink cable converter. It passes through DTS and DD well. Stereo sources as well. The mini requires no hacking as well.
If you take the read and compare problems between all the platforms you will not see much mention of the Mini here in the forums. That is good. Mentions come mostly from those with older mini's who made hardware changes. The new mini has the geforce 9400 gpu and a variety of intel core two duo chips to choose from.
With the new ipad coming (the ideal remote control in my mind) your customers will still be assured the early adopter status that keeps the money coming in for you.
http://www.youtube.com/watch?v=SlG8LC1eXgI
http://www.youtube.com/watch?v=-LrRp3O9ub8
Are a couple videos I took of XBMC running on my mini. PM me with any requests and I will be happy to take more video or share anything I have implemented.
Almost forgot to mention. I use an Apple Airport Xtreme and an Airport Express in WDS mode. It puts media as the top priority on the network and makes a great handshake. Two wireless stations at my home that make one SSID on a scan. "Meshing" is easy thanks to apple. I stream 720P wireless (due to home configuration) and still download up to 700kb/s with smooth playback. MY DD-WRT based linksys WRT-300N has been re boxed due to locking up too many times.
Linux is great and fun but when money and customers are on the line get something with a warranty would be my best advice. In 2004 I was communication with hardware vendors about a custom net top box and server backend. My current config is the bees knees on that level. If you need a server go Mac pro or Xserve, even an older one. They support fiber cards and more ram than any other hardware out there. All apple products these days are unix in the background.
