Audio question for HTPC build

Hi,

I am looking for info and advice on a HTPC build related to audio. I bought recently a nice set of speakers (5.1) for my home theater and I also got a decent yamaha receiver. I love music and look forward (among other things) to playing my itunes library on my new stereo equipment.

When I build my system I have the option to use the onboard audio on the Mobo or buy a sound card, say like an Asus Xonar 1.3. For regular PC use I can see why having a sound card is better than onboard audio. The sound card does the digital to analog conversion to drive the PC speakers better, for various reasons like better filtering, SNR etc. Plus it offloads the CPU some with audio work. But for a HTPC build, if I send a digital stream to the receiver, the receiver is doing the digital to analog conversion, and will do a quality job. Am I right in this assumption? Will there be a discernable audio quality difference between onboard and discrete audio for this case?

I am looking for quality, but if there isn't much difference it would be a shame to buy a sound card that is not needed.

Looking for help, thanks

Jim