Ok, I'm waiting on my new mac pro to arrive (Tuesday...) In the mean time I've been taking a quick inventory of what I'll be able to move over from my other older systems. In the process, I looked at my current Logitech THX 5.1 speaker setup and was dismayed to find that it only has Front L/R, Rear L/R, Center inputs, and not Optical SPDIF! So I swung by Frys and Best Buy... Neither had a single computer speaker setup that had SPDIF (Optical or Coax) in stock... Looking at newegg, it doesn't look like they carry any that do either! ARGH!!! How do you guys get 5.1 audio on your Mac Pro's???? I really don't want to resort to purchasing a $200+ receiver (which pumps out a ton of heat and takes a lot of space) just to get decent audio out of my new machine! Options???