Babou,
I recently went through something similiar. I got fed up with the persistent hiss on my built-in sound card as well as occasional flaky behavior such as slight sputtering when the computer was under heavy load.
I did a lot of research and talked to some heavy gamer friends and bought an M-Audio Revolution 7.1 card. I have been very happy with it. The hiss is gone, even when I crank the volume all the way up, and it has been pretty solid performance wise. M-Audio is a German digital audio company that has been working in the pro and semi-pro world for a while. The Revolution 7.1 has gotten some of the best reviews out there.
Now I’ve been thinking about upgrading my speakers (I have an Altec Lansing 5.1 cube speaker set now and the cubes just don’t have much oomph)…
Their board is built on the Via Envy 24HT. Since Via is a Taiwanese company, you’ll probably find something based on this chipset here. However, ratings and performance of different brands will not be the same as the analog hardware can be different. I bought my board in the US and it cost about US$95. Since you asked about Creative, their Audigy Gamer board is based on this chipset and has gotten decent reviews.