There is hype and there is reality.
For the vast majority of users there is absolutely no significant difference
in performance between Creative cards, and their twitchy, poorly supported
drivers, and modern motherboard based audio.
Many Creative sound card users get only basic functionality out of their
cards. The add-on Creative software does not work or only some of the
applets work.
If your motherboard has onboard sound you may want to try it before
investing in what may be a troublesome Creative card.
It is more likely that your speakers or headphones limit audio performance
far, far more than the motherboard based audio.
If your motherboard does not have onboard video your hardware is probably so
old that you would be better off upgrading than buying a new video card.