A note about that the " Creative Sound Blaster X-Fi Xtreme Audio 7.1 Channels 24-bit 96KHz PCI Interface Sound Card "
A year or so ago, Creative changed the name of this card. It currently holds the X-FI name; however, it does not use the X-FI chip that the higher end more expensive X-FI cards ($70+ cards). It's actually their older chipset, I think it still may be based off of the LIVE series of cards.
You're getting what you pay for. It is a step up from an Onboard Audio Chip, but won't hold a candle to the higher end X-FI cards.