Do not hesitate to upgrade your on-board audio to this ASUS Xonar DG. Even with a $300+ mother boards, you are still stuck with Realtek or Cirrus Logic audio chipsets which can not outdo a good quality ASUS Xonar or Creative X-Fi card.
If you have a good 2.1 channel system or just use headphones, this card will provide near-audiophile quality sound clarity and details. If you are considering the optical 5.1 out, go for a better card. The SPDIF out controls from the software interface can sometimes be non-responsive and will provide you with no digital output.
For $30, this is the most affordable quality audio upgrade you can purchase. Creative Labs have not been doing too well in recent years and their low end cards generate average sound crispness and they are leaned towards gaming audio development which makes their product lines such as the new Recon3D unsuitable for music listeners.