In the past I've used my powerbook hooked up to my system with a USB audio out with favorable results. I was able to use my cell/pda (Sony Ericsson p910i) as a bluetooth remote using the shareware program Salling Clicker, which allowed me to fully control and search itunes (and even the mouse if I wanted to) via the phones graphic interface/touchscreen. I only used the laptop as a jukebox for entertaining or casual listening (yep, it happens from time to time) and when I install my system in my new house I'm going to get a mac mini as a dedicated music server which I will also hook up to my plasma. I was initially all excited by the Olive, but I think anyone with a little ingeniuty can come up with an acceptible and more customizable solution, albeit not in one box. I think the bluetooth/pda controller option is the way to go for those of you interested.
