This!
It took me a while to figure this out. You can see my comments in the same article linked. However I'm thinking a digital input/output such as an HDMI cable will do the job without compromise. You just need to hook up your display to the AV receiver.
A sound card is basically a compact DAC (digital to analogue converter) and amplifier, that would work fine with small speakers such as Corsair 2500 or Logitech Z906. a dedicated AV receiver has all that and in better quality, and can be hooked up to some serious speakers, another heavy investment.
An AV receiver can serve all your electronics; TV, sound system, consoles, including your PC.
If the space on your motherboard is more precious to you than your living space and your money (me for example:rofl
, a dedicated (preferably network capable) AV receiver is the way to go.
Now you can build that powerfull mitx rig or that CF/SLI atx build without using onboard audio.