Broadband Alternatives to WebTV?

tlon asks: "A friend recently approached me asking if there are any hardware alternatives to WebTV that allow for high speed internet access. For the unaware, WebTV is a dial-only solution, and does not allow for broadband. While there are several promising digital dish solutions cropping up, I've found none that leverage high speed cable networks. What set-top solutions are available for the computer illiterate consumer that allow access via a broadband network (aka Cablemodem). Perhaps some of these solutions leverage Linux on the back end?"