I love hard disk video recorders because they surprised me by being much more than super-fancy VCRs. They changed the nature of the way people watched TV in ways I didn't expect.
Now I've been working with MythTV which is an open source PVR. I have a new program in development, and if any of the readers out there are using MythTV I wouldn't mind some folks to test it out before I announce it to the Myth community.
This program does many things, including two things that I think could change the nature of how TV is chosen.