I have two Apple TV's (version 1) and one Airport Express that I use in three different rooms. The two ATV's are connected to DAC's (PS Audio and Proceed) via Wireworld SuperNova 5 glass toslinks while the AE uses analogue out to a pair of Audio Engine self powered speakers. I have about 1700 CD's stored on a 1T hard drive ripped in Apple Lossless. It all sounds very good.
For serious listening, I also use Pure Music in connection with Airfoil and find that it is a big improvement.
My favorite "find" has been broadcasting Pandora to my various sytems using Airfoil. If you spring for the premium edition of Pandora for $36/year, the signal is bumped to 192 KBS. No, it is not audiophile quality, but it sounds good enough for the type of background listening (such as dinner parties) that I primarilty use it for, plus I have discovered lots of new music. My CD purchases have dropped about 90% since I started listening to Pandora. BlueBeat also has some great stuff that I broadcast with Airfoil. KUT FM (University of Texas at Austin) has a program on Saturday nights called "Twine Time" covering blues, R&B and rockabilly that I have listened to for years when I could get the signal down in Texas, and now it is a Saturday night ritual.
I suppose I should spring for a Mac Mini for my main rig, but for now, I am a happy camper