All my pc builds i always used a dedicated sound card i have never been to keen using onboard sound, i looked at your link with the creative sound blaster Zx. Creative sound cards are my prefered card, I'm using the ZxR model in my Rampage IV Extreme and it sounds great with the logitech Z5500 speakers so the Zx should have a decent quality sound. But it's a personal choice on what card to buy as some people like Asus and some like Creative and many people do prefer onboard sound...Anyways good luck with your decision.
Motherboard, Asus Rampage IV Extreme.
Case, Coolermaster Cosmos II Ultra Tower.
CPU, Intel i7 3930k.
GPU, Asus Nvidia GeForce GTX 780.
OS HDD, SSD Intel 520s 240gig.
Memory/Ram, Corsair 16gig (4X4) Dominator GT 2133mhz.
Sound Card, Creative Sound Blaster ZxR.
PSU, Corsair AX-1200i.
Watercooling, Corsair H100i.