With the availability of high capacity hard disks and MPEG encoders/decoders the idea of a fully digital video recorder comes to mind.
There are already two commercial products: “ReplayTV” from Replay Networks, Inc. (www.replaytv.com) and “TiVo” from TiVo, Inc. (www.tivo.com). Both systems are mainly targetted on working together with special services provided by the system manufacturer, which offer the consumer a personalized recording strategy.
The downside of these systems is the lack of a useful “timer recording” facility, and the manufacturers’ tendencies to implement new ways of imposing advertisements on the viewer (since it would become too easy to skip the commercial breaks). They also don’t support what one would expect to come natural with digital recording: on-disk editing.
Neat project, build your own TiVO.