TiVo and cable companies usually charge around 10 bucks a month for DVR service. A do-it-yourself PC solution will leave you with one fewer monthly bill to pay.
Ditch the DRM.
When you record TV to your PC, you can burn and copy the content on your own terms without the copyright-protection schemes that encumber services such as TiVo To Go.
Why clutter your office with a TV and a computer? A DVR-enabled PC has all the benefits of a television, a computer, and a recording device in one package.