The Tech Report Dell has adopted the Bigfoot Killer NIC for some of its gaming PCs:
Dell seems to remember the Killer NIC too, because we just received a press release saying the PC maker now offers the Killer NIC K1 in its XPS 630 and XPS 730 gaming desktops. Dell lumps the card together with Nvidia's PhysX card under the "Gaming Essentials" section of its PC customization page, and it charges $149 for it. That's about what you can expect to pay at online retailers these days.
The Killer NIC slightly reduces lag in games but is a quite expensive solution.