According to theInquirer Creative is set to launch a PCIe based X-Fi sound card in the second half of this year. This has taken way to long. PCIe was launched 3 years ago and it has taken that long for the best sound card maker to create a sound card for those PCIe x1 slots.
Over the past 3 years PCIe slots have become more and more common and that PCI slot has been slowly lowering in numbers on those motherboards out there.
I personally only use one PCI card and in modern motherboards that have an over abundance of USB ports and Ethernet ports the only thing that I think I would ever put in a PCI slot is a TV tuner card or a sound card. If I could start putting those in PCIe slots instead I would be more then willing to do so.
(PCI Creative XtremeGamer pictured)