My frustration with the audio hookups is that the Pro doesn't use the PC Standard 3 mini-din jacks for 5.1 sound (Front L/R, Rear L/R, Sub/center). As such, if you want surround sound, you either gotta hook the pro up to a full-on stereo setup, or buy the ONLY computer 5.1 setup that takes TOS-Link input - the Logiteck Z-5500...
I game on my Pro (under Windows 7) and really need 5.1 sound, but as things currently stand, I'm stuck. I've got 2 5.1 computer speaker setups, I'm not about to drop ANOTHER $300 on the Z-5500's. Just annoying!!!! I COULD go get a SB X-Fi PCI-E card, but then I'd have to switch back and forth the speaker setups when playing stuff in Windows vs. OSX.
I just don't get why a computer that is sold mostly for audio/video professionals has such CRAP audio out options!