My family dumped our cable TV last Spring, relying strictly on DVD and over-the-air broadcasts of HDTV for the few
hours minutes a month of TV-watching we do. All analog TV sets (i.e. virtually set except those purchased in the past few years) will stop working entirely at midnight, February 17, 2009 -- just over a year from now -- when the entire United States switches over to digital TV broadcasting. You probably won't notice if, like most Americans, you get your TV exclusively from cable, but any sets that rely on over-the-air broadcasts will be looking at dead air unless you have a digital TV converter box.
The good news is that Congress has created a program to give away $40 coupons toward the purchase of a converter box. I just applied for one at the https://www.dtv2009.gov/ web site. Not sure what the full cost of the boxes will be, but my guess is that the Big Retailers will have at least one model you can get basically for free. Anyway, it's worth signing up, especially if you have a spare TV someplace not connected to cable, since otherwise your TV set will become nothing more than a useless heavy object.