clutchc :
It will be a great improvement over on-board sound quality for an audiophile. But if you are a gamer and want to free up the CPU cycles that the on-board sound chip uses, I believe the card you mention does not have its own processor. That means it will still rob cycles from the CPU. But with SB or IB processors, that's not really a big deal.
CPU usage (onboard vs dedicated) is a non-issue now. There was a time it mattered but not now. I didn't even register 1% CPU usage before I added my sound card when playing CD's in 5.1 surround. CPU's are also rarely a bottleneck so unless your CPU hits 100% usage it's impossible to affect a games frame rate by adding a dedicated audio card.
Audio quality:
As mentioned motherboard audio is adequate for most. You probably need a minimum of $50 stereo, $80 2.1, or $120 5.1 speaker setups before a quality dedicated sound card would sound better.
I compared these two audio solutions with my great M-Audio AV40 stereo speakers:
Realtek 889 vs Auzentech Forte X-Fi (PCIe)
Low quality audio sounds identical to my ears. However, my MUSIC, MOVIES and GAMES often sound far better with the Forte dedicated card. In some of the music I could really hear the separation between instruments, bass was better and I heard noises that the onboard Realtek chip either didn't process or simply washed out.